Burr ML, Butland BK, King S, Vaughan-Williams E (1989). Changes in ...... Zeiger RS, Heller S, Mellon MH, Jeffrey W, Falkoff R, Schatz M (1991). Facilitated ...
IMPROVING THE MANAGEMENT OF CHILDHOOD ASTHMA
By Md. Sanaur Rahman Khan
A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy (Ph.D.) in Paediatrics in the School of Women’s and Children’s Health, University of New South Wales.
FEBRUARY, 2003.
Improving the management of childhood asthma
Certificate of originality I hereby declare that this submission is my own work and to the best of my knowledge and belief, it contains no material previously published or written by another person, nor material which to any substantial extent has been accepted for the award of any other degree or diploma of a university or other institute of higher learning except where due acknowledgment is made in the thesis. Any contribution made to the research by others, with whom I have worked at UNSW or elsewhere, is explicitly acknowledged in the thesis. I also declare that the intellectual content of this thesis is the product of my own work, except to the extent that assistance from others in the project’s design and conception or in style, presentation and linguistic expression is acknowledged.
Md. Sanaur Rahman Khan. Student ID: 2263128
I
List of Publications: 1) “Outcome evaluation of early discharge from hospital with asthma” -Khan MSR, Henry RL, Hurst T Respirology 2003; 8: 77-81. 2) “Background severity of asthma in children discharged from emergency department” - Khan MSR, O’Meara M, Henry RL. - Accepted for publication in Journal of Paediatrics and Child Health in November, 2002.
II
ABSTRACT: Objectives: To improve the management of childhood asthma. Subjects & Setting: Children admitted with asthma from 1st January 2000 to 31st December 2000; and children discharged with asthma from Emergency Department (ED) of Sydney Children’s Hospital (SCH) between 16th October 2000 and 28th February 2002.
Methods: There were two major studies addressing aspects of asthma management, namely the retrospective in-patient study and the prospective ED presentation study. Each of these was subdivided in two different studies to address different research questions. In the first retrospective study, a priori criteria for theoretical "time ready for discharge" (TRD) for asthmatic admissions were defined based on frequency of use of salbutamol. In the second retrospective study, we followed 361 children for 1 year from the date of their discharge, to find out whether those who received asthma education, written asthma action plan, and preventer medications at the time of discharge and whose follow–up was arranged prior to discharge, represented to the ED or were readmitted. The prospective study, which also addressed two different research questions, was a randomised-controlled trial in which parents of 310 children who had been discharged from ED with asthma, received written asthma materials only or received telephone consultation in addition to written materials. Background severity and control of asthma were assessed in baseline study from parent’s reported symptom frequency and medication uses.
III
Outcome measures: readmission and representation to the ED, regular use of preventer medications, possession and use of written asthma action plan, and asthma symptom measures.
Results: (1) 116 (27.7%) children were discharged before our theoretical TRD and only 2 child who were discharged after achieving TRD, developed symptoms which required oxygenation and more frequent doses of salbutamol. Both readmission and representation to ED within one week of discharge were uncommon. (2) 121 children represented within 1 year of their discharge, of whom 68 children were readmitted. Both receiving asthma education during admission and arranging follow-up prior to discharge were associated with a decreased likelihood of representation as well as readmission (P < 0.001). (3) In RCT, the baseline study showed that 14% of children were not receiving appropriate preventer therapy despite indications; and a further 34% had frequent symptoms despite receiving preventer therapy. 62% of the parents reported of having written asthma action plan but less than 50% of them reported using it regularly. At follow up we observed both possession and use of written asthma action plan (p = 0.002) as well as regular use of preventer medications (p = 0.001) were improved in the intervention group compared with the control group.
Conclusions: Discharge on 3-hourly rather than 4-hourly doses of salbutamol appears safe and shortens length of stay by an average of 5.5 hrs. Both asthma education and follow-up at the time discharge appear to reduce readmission and representation to ED. Telephone consultation can increase the regular use of preventer medications and written asthma action plan.
IV
Acknowledgments: My indebtedness and heartfelt gratitude goes firstly to my supervisor, Professor Richard Henry, for his kind support, encouragements and guidance throughout my whole study period. His strong and relentless support boosted my confidence and kept me strong during the difficult period of my life. I am so much grateful and indebted to Professor Henry for accepting me as his Ph.D. student and allowing me informal access to him despite his extremely busy schedule.
I am deeply
appreciative of him for his insightful written comments on the manuscripts, guidance and thoughtful suggestions on different aspects of the thesis. It would have never been possible to complete this work without his very personalized care and support. My sincere thanks are due to my co-supervisor Dr. Madelen Gazarian, for her support, suggestion, guidance and supervision during the early part of my study period. I am grateful to her for spending her precious time to guide me in the early part of my study. My gratitude and indebtedness extends to Dr. Matthew O’Meara, Director of Emergency Department, Sydney Children’s Hospital for his interest, his ideas, support and for allowing me to conduct my research and accessing parents in his department. I am also grateful to his team of doctors and nurses especially to his consultants Dr Chris Webber, Dr Vasili Berdoukas and nurses Darren, Diana and others for paging me to inform about the patients, helping me in recruiting patients and for encouraging the parents to participate in this study. They also help me recruiting patients in my absence.
V
Thanks are also due to other staff working in the Emergency Department for their friendliness and patience especially triage staff. I gratefully acknowledge the contribution of my beloved teacher late Professor Behjat Ansari, ex-Professor of Paediatrics, University of Glamorgan, Wales, United Kingdom and ex-editor, Welsh Paediatric Journal, who inspired me to join a Ph.D. course under his supervision but could not complete because of his sad demise. My deepest thanks and sincerest gratitude are due to Dr. John Morgan and Dr Abbas Latif, consultant paediatricians, Royal Glamorgan General Hospital, Wales, U. K. for their support in the absence of Professor Behjat Ansari. My sincere thanks also extend to: Mr. Georgios Liangas for his assistance in recruiting some of my patients. Ms. Tara Hurst for all her statistical help. Ms. Sophia Adamo and staff from Medical Records department of Sydney Children’s Hospital for their help in pulling out medical charts of children admitted with asthma in the wards of SCH. Ms. Sandy Wales, Ms. Amanda Byrnes and Ms. Donna Jelley for their support and help in pilot study, educating parents and conducting telephone consultation. Ms. Linda Christie, Data Manager, ED computer system for helping me in retrieving various data from computer. Ms. Laddar Leephokharnon for computer support. Ms. Martha Gonzales, Mr Ian Stubbin and Mr Ben of Prince of Wales medical library for their help and support in retrieving articles from journals and Medline. I gratefully acknowledge the infrastructure support provided by Asthma New South Wales to conduct telephone consultations in our study.
VI
Thanks are due to Ms. Margo Lemcke of Asthma NSW for her generous support. I am especially thankful to Ms. Annette Burgess for her administrative support and care during my study period. Thanks are also due to Ms. Kathy Profiris, Ms. Carolyn Green and Ms. Sandy Richardson, Secretaries of School of Women’s and Children’s Health for their help, pleasant behaviour and support. I gratefully acknowledge the generous participation of all the parents and children who took part in our study.
Many of them showed remarkable interest and
encouraged us to continue the program. Special thanks to them for their cooperation. I am also grateful to Financial Market Foundation for Children for their generous financial support to conduct our studies. I am grateful to my elder brothers for their blessings and encouragement. My thanks and gratitude are due to my eldest brother for his constant blessing and encouragement through e-mail. I am especially grateful and indebted to my elder sister Mrs. Nurun. N. Khan and brother-in-law Mr. Abdul. Q. Kazol who clothed and fed my family and me from USA. Without their help it would not be possible for me to reach to the end. Last but not least, I am indebted to my wife Dr. Shamim. A. Khan and to my daughter Ms. Sanjeena Khan for their inspiration and encouragement to my effort to finish this great task. I am grateful to them for consistent support during our hardship and struggle.
Above all, I am grateful to almighty God for giving me the opportunity to serve for the people.
VII
Dedicated To The memory of my beloved Parents Ahidur R Khan and
Mastura Biwi -
whose
feelings.
remembrances
always
strengthen
my
inner
VIII
Table of Contents: List of Publications:--------------------------------------------------------------------- I Abstract:------------------------------------------------------------------------------------- II Acknowledgment:----------------------------------------------------------------------- IV
Chapter 1: Introduction 1.1
Literature review------------------------------------------------------------------1 1.1.1 Increasing prevalence of asthma----------------------------------- 1 1.1.1.1
The prevalence of asthma & its variation------------------------- 2
1.1.1.2
Is the prevalence of asthma increasing?-------------------------- 3
1.1.2 Increasing severity of asthma--------------------------------------
6
1.1.2.1
Asthma mortality data----------------------------------------------- 6
1.1.2.2
Hospitalisation data-------------------------------------------------- 12
1.1.2.3
Emergency Department attendances and management-------- 30
1.1.3 Barriers to asthma control----------------------------------------------36 1.1.3.1
Asthma severity vs Asthma control------------------------------- 36
1.1.3.2
Treatment related barriers to adherence------------------------- 38
1.1.3.3
Physician related barriers to adherence----------------------------41
1.1.3.4
Patient/parental related barriers to adherence-------------------- 43
1.1.3.5
Physician-parent interaction related barrier-------------------- 46
1.1.4 Management of asthma------------------------------------------------- 49 1.1.4.1
The natural history of asthma-------------------------------------- 51
1.1.4.2
Classification of pattern of asthma-------------------------------- 59
IX
1.1.4.3
Maintaining best lung function------------------------------------ 62
1.1.4.4
Achieve & maintain best lung function by medication--------- 65
1.1.4.5
Making appropriate treatment decision--------------------------- 72
1.1.5 Provision of written asthma action plan--------------------------- 77 1.1.6 Asthma Education------------------------------------------------------- 81 1.1.6.1
general aspects of childhood programs-------------------------- 81
1.1.6.2
goals and objectives of asthma education----------------------- 82
1.1.6.3
behavioural factors related to asthma morbidity----------------- 86
1.1.6.4
theories of health education underlying asthma prevention---- 87
1.1.6.5
behavioural influences related to asthma prevention---------- 95
1.1.6.6
review of childhood asthma self-management programs---- 100
1.1.7 Outcome measures in asthma-------------------------------------- 108 1.1.7.1
asthma related outcome measures-------------------------------- 111
1.1.7.5
summary of outcome measures----------------------------------- 135
1.2
General background-setting the scene --------------------------------- -136
1.3
Hypotheses and aims--------------------------------------------------------- 148
Chapter 2: Methods of studies undertaken 2.1 Retrospective in-patient study --------------------------------------------149 2.1.1 outcome evaluation of early discharge from hospital--------------------- 150 2.1.2 Asthma education and follow-up protects children------------------------ 153
2.2 Randomised controlled trial of asthma education--------------- 155
X
Results and Discussions section: Chapter 3: Outcome evaluation of early discharge 3.A Results-------------------------------------------------------------------------- 174 3.B Discussion--------------------------------------------------------------------- 181
Chapter 4: Asthma education and follow-up can protect children 4.A Results---------------------------------------------------------------------------187 4.B Discussion---------------------------------------------------------------------- 195
Chapter 5: Background severity of asthma in children 5.A Results--------------------------------------------------------------------------- 201 5.B Discussion---------------------------------------------------------------------- 209
Chapter 6: Randomised controlled trial of asthma education 6.A Results-------------------------------------------------------------------------- 214 6.B Discussion----------------------------------------------------------------------234
Chapter 7: General Discussion & Conclusion 7.1 General discussion----------------------------------------------------------- 242 7.2 Conclusions------------------------------------------------------------------- 262
References:----------------------------------------------------------------------------
263
Appendices: Appendix 1:-------------------------------------------------------------------------- 365
XI
Appendix 2:------------------------------------------------------------------------- 369 Appendix 3:------------------------------------------------------------------------- 373 Appendix 4:-------------------------------------------------------------------------- 380 Appendix 5:-------------------------------------------------------------------------- 384 Appendix 6:-------------------------------------------------------------------------- 389 Appendix 7:-------------------------------------------------------------------------- 390
Figures & Tables: Fig 1.1-------------------------------------------------------------------------------- 97 Fig 1.2---------------------------------------------------------------------------------138 Fig 1.3-------------------------------------------------------------------------------- 139 Fig 2.1-------------------------------------------------------------------------------- 164 Fig 2.2-------------------------------------------------------------------------------- 167 Table 1.1---------------------------------------------------------------------------- 124 Table 3.1----------------------------------------------------------------------------- 175 Table 3.2----------------------------------------------------------------------------- 178 Table 3.3----------------------------------------------------------------------------- 180 Table 4.1------------------------------------------------------------------------------ 188 Table 4.2----------------------------------------------------------------------------- 190 Table 4.3----------------------------------------------------------------------------- 192 Table 4.4----------------------------------------------------------------------------- 193
XII
Table 4.5------------------------------------------------------------------------------ 194 Table 5.1----------------------------------------------------------------------------- 202 Table 5.2----------------------------------------------------------------------------- 205 Table 5.3----------------------------------------------------------------------------- 206 Table 5.4----------------------------------------------------------------------------- 208 Table 6.1---------------------------------------------------------------------------- 215 Table 6.2----------------------------------------------------------------------------- 216 Table 6.3----------------------------------------------------------------------------- 219 Table 6.4----------------------------------------------------------------------------- 220 Table 6.5----------------------------------------------------------------------------- 221 Table 6.6---------------------------------------------------------------------------- 224 Table 6.7----------------------------------------------------------------------------- 227 Table 6.8----------------------------------------------------------------------------- 230 Table 6.9----------------------------------------------------------------------------- 233
1
CHAPTER 1: Introduction 1.1 Literature review 1.1.1 Increasing Prevalence of Asthma “One morning, a mother rang me in my office. She knew my number, because I had contacted her earlier to enrol her child in one of our studies about asthma. She and her husband had migrated from Chile 20 years previously. They could hardly remember any allergy or wheezing while they were in Chile. When they arrived in Australia, the husband developed allergies and their elder son who is 4 years old and who was born in Australia had some bouts of dry cough a few months earlier. The GP had treated him with cough linctus. One night their son developed severe cough with wheeze. The ED doctor at SCH diagnosed asthma and treated him. Now the mother is pregnant with her second child and she is anxious to do anything she can to avoid asthma in the second child. She wanted to know, what does asthma means? Why is asthma more prevalent here in Australia, but not in her ancestor country Chile? Can she prevent asthma in her second child? “
This case history summarizes many of the issues they need to be addressed, including perceptions that asthma prevalence has increased and that asthma is more common in Australia than in other parts of the world. Asthma is the most common chronic illness in children, the major reason for admission to hospital in Australia and the major chronic condition associated with absence from school.
2
1.1.1.1 The Prevalence of Asthma and its variation around the World The prevalence of asthma varies widely throughout the world, ranging from less then 1% in some developing countries to more than 25% in some developed countries (Robertson, 1995). The International Study of Asthma and Allergy in Childhood (ISAAC) steering committee (1998) in their worldwide study found the highest prevalence of asthma in United Kingdom, Australia, New Zealand, and Republic of Ireland followed by USA and the lowest prevalence in several Eastern European countries, Indonesia, Greece, China, Taiwan, Uzbekistan, India and Ethiopia (ISAAC, 1998). The prevalence of asthma, defined as ‘a history of wheeze in the past 12 months’ in children and adolescents is estimated to be as high as 24.6% for children of age group 6 to 7 years and 29.4% for the 13-14 years age group in Australia (ISAAC, 1998; Robertson et al, 1998), 18.7% in New Zealand (Mitchell & Asher, 1994), 15.9% in England (Strachan et al, 1994). The prevalence was found to be much lower in Switzerland at 7% (Robertson, 1993). Robertson et al (1993) compared the prevalence of asthma in Australia, Chile and Switzerland using the same instrument. They found that the prevalence of asthma in children aged 12 years was similar in children from Australia (20.9%) and Chile (21.1%), but significantly lower in Switzerland (6%); for 7-year olds it was 23.1% in Australia, 26.5% in Chile and 7.4% in Switzerland. They suggested that genetic, educational and environmental factors might be responsible for regional differences in asthma prevalence (Robertson et al, 1993).
3
1.1.1.2 Is the Prevalence of Asthma increasing? In each country where serial measurements have been made, there has been a consistent rise in the prevalence of asthma (Robertson, 1995). Studies in the same populations over time suggest that the prevalence of both wheezing and diagnosed asthma has increased.
Ng Man Kwong et al (2001) found significant increases in the prevalence of asthma in 8-9 year old English children between surveys in 1991 and 1999 (19.9% in 1991 versus 29.7% in 1999; p < 0.001). The prevalence of wheeze in the previous 12 months had also increased from 17% to 19.4% (p < 0.01) (Ng Man Kwong et al, 2001).
In Australia, studies in Melbourne school children from the 1960s to 1990s show a consistent increase in the prevalence of lifetime history of wheeze from 19% in 1969 to 41% in 1990 (Robertson et al, 1991). By analysing 18 studies of asthma prevalence in Australian children between 1969 to 1992, Bauman found an average increase at a rate of 0.7% per annum (Bauman, 1993). Peat et al (1994) conducted a study on changing prevalence of asthma at two environmentally different towns of Wagga Wagga and Belmont in New South Wales in 1982 and 1992. They showed an increase in the prevalence of wheeze in those two towns over 10 years, from 13.0% in 1982 to 25.4% in 1992. A similar study in Tasmania, demonstrated an increase of 112% in the life time prevalence of wheeze over a period of 24 years from 1964 to 1992 (Jenkins et al, 1994).
4
Robertson et al (1998) as an Australian arm of the International Study of Asthma and Allergy in Childhood, conducted a prevalence study in Australian school children and found the prevalence of recent wheeze increased from 23.1% in 1990 to 27.2% in 1993 and the rate of increase was 1.4% per annum. The Australian Asthma Management Handbook, (NAC, 2002) summarises that there is evidence of increasing asthma prevalence and severity in Australian children and that asthma ranks among the ten most common reasons for seeing a general practitioner and the most common medical cause for hospital admission in children.
In Croydon UK, Anderson et al, determined prevalence and severity of childhood asthma in the 7 to 8 year age group using the same schools and a similar questionnaire in 2 different surveys and found an increased prevalence of wheeze from 9.7% in 1982 to 12.3% in 1991 (Anderson et al, 1994).
In Cardiff UK, Burr et al found the increase in prevalence of wheeze was 55% over 15 years and that doctor diagnosed asthma rose from 4 to 9% (Burr et al, 1989).
In Aberdeen UK, 7-year old children were studied in 1964 and again in 1989, during which interval the prevalence of wheezing had doubled from 10% to 20% and diagnosed asthma had risen from 4% to 10% (Ninan, 1992; Sears, 1997).
In addition to a questionnaire-based study, Peat et al (1994) measured the bronchial hyperresponsiveness to histamine in children from both Belmont and Wagga Wagga in New South Wales. The prevalence of bronchial hyperresponsiveness to histamine
5
in these children was 9.1% in 1982 and 19.8% in 1992, an increase of 117% over the 10-year period. This increase occurred predominantly in the atopic group of children (Peat et al, 1994).
Another repeat study was conducted on Welsh children by Burr and his colleagues in 1989. They included the measurement of bronchial responsiveness by using free running
exercise
as
the
provoking
stimulus.
In
that
study,
bronchial
hyperresponsiveness to exercise increased from 6.7% in 1974 to 7.7% in 1988 (Burr et al. 1989).
There is now both subjective and objective evidence of a true and substantial (approximately two-fold) increase in the prevalence of asthma, asthma-like symptoms and bronchial responsiveness over the past decade, in Australian children (Mellis, 1994). It is beyond the scope of this thesis to address possible explanation for these increases. Clearly asthma is a very important condition in Australian children. Its underlying severity is also a major issue.
6
1.1.2 Increasing Severity of Asthma An important component in the management of asthma is to define its severity (Phelan et al, 1995; NAC, 2002). Severity of asthma is sometimes used to refer to the underlying severity of background disease and sometimes to the severity of acute exacerbations.
Traditionally, overall asthma severity has been defined by various combinations of symptoms, medication requirements, pulmonary function abnormalities, quality of life, admission to hospital and even mortality (US Departments of Health and Human Services report, 1992; Cockcroft and Swystun, 1996).
1.1.2 Indicators of asthma severity Since the 1970s, the incidence, prevalence, morbidity and mortality have been increasing (Smith et al, 1997; Lenney, 1997) and this increase is disproportionately higher for children living in urban and low-income environments. The increased morbidity is reflected in days lost from school, worsening quality of life, increased hospitalisation rates, increased intensive care admissions, and increased emergency department visits (NAEPP, 1997; NAC, 2002).
1.1.2.1 Asthma mortality data Most asthma deaths result from acute exacerbations and many are potentially avoidable. Increases in asthma deaths, especially those persisting over a long period raise concerns about changes in asthma’s underlying prevalence or severity, or about
7
its management. The rate of death from asthma varies widely by age and disease severity (Silverstein et al, 1994) and is particularly high in certain populations such as inner-city African-Americans (Weiss et al, 1992a) and other underprivileged populations (Senthilselvan, 1995). In Australia, asthma mortality had more than doubled between 1979 and 1985 (NHMRC report, 1988). Since the late 1980s the trend has been reversed and there has been a steady decline in death rates due to asthma (Comino & Bauman, 1998). Other studies also showed a decline in asthma deaths over the 10 year period ending in 1995 in different parts of world (Campbell et al, 1997; Haahtela & Klaukka, 1998). In 2000, 454 Australians died from asthma (NAC, 2002).
Mortality is a clear measure of asthma severity. Such data are almost universally accepted and represent the ultimate measure of management failure. Researchers have proposed a profile of patients at risk of dying from asthma (Carswell, 1985; Newcomb & Akhter, 1985; Rea et al, 1986; Miller & Stunk, 1989). This profile includes such characteristics as: chronic severe asthma, recent hospitalisation for asthma, a prior life-threatening attack, poor compliance, psychosocial disturbance and a previous episode of respiratory failure due to asthma (Newcomb & Akhter, 1985). Greenberger et al (1993) also included under-treatment with antiinflammatory medications and lack of physician contacts within the last year as potential risk factors. Campbell et al (1996) in a case series found that regular use of beta-agonist bronchodilators and under-utilization of inhaled and oral corticosteroids were common among patients experiencing a near fatal attack of asthma. In the epidemic
8
of asthma deaths that occurred in United Kingdom in 1960, investigators presumed that the increase in deaths was largely attributable to the introduction of a high dose, over the counter sympathomimetic agent and a subsequent over reliance on this medication and under use of corticosteroid (Speizer and Doll, 1968; Vollmer, 1994).
In differentiating fatal and near fatal asthma in children, Schmitz et al (2000) reported that fatal asthma patients were older than near fatal asthma patients and rapid-type onset was more common in fatal asthma patients. However, respiratory tract infections were higher among near fatal asthma and long-term regular use of short acting beta agonist was common in both groups. The authors concluded that the analysis of near fatal asthma in elucidating the causes of fatal asthma in children might be of limited value because of significant differences in clinical aspects in children. Martin et al (1995) in another study reported that most paediatric cases of near fatal asthma had sever asthma, significant denial, psychosocial pathology, history of delay in seeking care and most of them (53%) were older age group children.
Several case control studies have been conducted to assess the effects of beta agonist on death from asthma (Crane et al, 1989; Pearce et al, 1990; Graigner et al, 1991; Spitzer et al, 1992). Studies from New Zealand emphasized the possible role of one particular bronchodilator, fenoterol, while suggesting that other bronchodilators did not similarly increase the risk of death from asthma (Crane et al, 1989; Pearce et al, 1990; Grainger et al, 1991). The first New Zealand case-control study, spanning the period 1981 through 1983, was based on 117 deaths from asthma in people aged 5 to
9
45 years and 468 controls matched with respect to age and ethnic group. The RR ratio of asthma deaths in relation to fenoterol was 1.55 (Crane et al, 1989). The second study, which spanned a different period (1977-1980), was based on 58 deaths and 227 controls; it found an odds ratio of 1.99 for asthma death in patients prescribed fenoterol (Pearce et al, 1990). The third New Zealand study, which spanned the period 1981-1987, was based on 112 deaths, but used 2 different control groups. Control group A comprised 427 patients who had been admitted to hospital for asthma during the calendar year that the corresponding death occurred and who had also had a previous admission for asthma in the previous 12 months. Control group B comprised 448 patients admitted to hospital for asthma during the calendar year in which the admission of the corresponding case occurred. The fenoterol odds ratio was 2.11 when group A was used as control and 2.66 when group B was used as control. The use of two control groups was to indicate that the association between fenoterol and asthma deaths was not an error related to control selection (Grainger et al, 1991). In all three studies, the three major markers of chronic asthma severity (Crane et al, 1992) (an admission in previous 12 months, use of more than three categories of prescribed asthma drugs and use of oral corticosteroids at the time of index admission) were found to increase risk of asthma death with fenoterol.
Robertson et al (1992) attempted to review the circumstances and evaluate the potentially preventable factors of all paediatric deaths from asthma in Victoria over a 3-year period. Among those deaths, 33% were judged to have had a history of mild asthma, 31% moderately severe and 36% to have had severe asthma. A total of 22% were reported to be symptom free in the 3 months prior to death and though 68%
10
had been hospitalized at some stages in their life, only 44% had a hospital admission in the 12 months prior to their death. In 39% of cases potentially preventable factors were evident and most common factors were; 1) inadequate assessment and treatment of prior asthma, 2) poor patient compliance, and 3) delay in seeking medical attention during the final attack. They found that in two-thirds of deaths the parents reported that their child’s asthma was either stable or improving over the 12 months prior to death. From the Victorian experience Robertson et al reported that the majority of deaths occurred in mild cases without identifiable risk factors and recommended adequate assessment of asthma severity to identify at-risk cases.
Garrett et al (1995) concluded that the decrease in asthma mortality was most likely due to an increase in use of inhaled corticosteroids, as reflected in the sales of these medications as a whole. On the other hand, some other cohort or case-control studies indicated that inhaled corticosteroid might not prevent death from asthma (Pearce et al, 1995; Hessel et al, 1999).
In Australia, the declining report of asthma mortality suggest that despite the increase in prevalence of asthma that has been observed over time, improved recognition and treatment has promoted a decrease in mortality. It is likely that this reflects the overall success of combined efforts to improve the awareness of and treatment of asthma in the community (Comino and Henry, 2001).
11
1.1.2.1.1 Preventable factors Robertson et al (1995) mentioned that in most studies of asthma mortality there were four preventable factors, which could be identified in two-thirds of patients. These factors were; 1) inadequate assessment of background severity of asthma and undertreatment with preventer therapy, 2) poor compliance with seemingly appropriate prescribed therapy, 3) inadequate recognition of severity of asthma attacks, 4) delay in seeking professional help.
Inadequate assessment of severity may be on the part of patients as well as physicians with failure to recognize symptoms, resulting in delay in seeking as well as starting appropriate therapy. Poor compliance with prescribed therapy is a major problem in the management of asthma and may contribute to increased morbidity and as well as to mortality.
Some of the key factors that contribute to delay in seeking appropriate professional help in an acute attack are inadequate recognition of an attack, lack of knowledge about asthma and its exacerbation, and denial of the severity of attack.
12
1.1.2.2 Hospitalisation data Hospitalisation for asthma is a good indicator of severity. Studies of asthma hospitalisation include the event itself as well as its characteristics such as length of stay, cost, and use of services as outcomes. Hospitalisation for asthma is also a significant predictor of death from asthma (Crane et al, 1992; Suissa et al, 1994; Tough et al, 1996) as well as for subsequent hospitalisation for asthma (Crane et al, 1992; Mitchell et al, 1994). The major advantages of hospitalisations as an outcome measure are that they represent a well-defined outcome; are readily available at national, state, and local levels; and can be uniformly coded throughout the world. Characteristics of the hospitalisation, such as length of stay, procedure rendered, and utilization of services also provide a rich array of measures with which to study patient management among patients with good and bad outcomes.
1.1.2.2.1 The economic burden of asthma hospitalisation Hospitalisations for asthma also account for an enormous share of the total cost of health care for asthma (Vollmer, 1994). Hospitalisations accounted for 47% of the direct costs of asthma and 27% of total costs (direct costs plus indirect costs, such as loss for working days) in the United States. In 1990, the total cost of illness related to asthma was estimated to be US$6.2 billion. Inpatient hospital services represented the largest single direct medical expenditure estimated at US$1.6 billion (Weiss, 1992). In 1993, the average cost of inpatient treatment at Children’s Hospital and
13
Medical Center in Seattle, USA for acute asthma was US$1200 per day (excluding intensive care unit care) (Morray & Gregory, 1995).
Smith et al (1997) estimated that the cost of asthma in United States in 1994 was US$5.8 billion (95% CI $3.6 to $8.1 billion). Hospitalisation accounted for more than half of all expenditure. The authors suggested that further asthma research and intervention should be concentrated on preventing hospitalisation and reducing severity of asthma, which could probably reduce expenditure and decrease health care resource utilization.
Wells (1994) quoting NHS, UK estimated the cost of childhood asthma in 1988. 52% of all admissions to hospital for asthma involved children aged 0-14 years with an average duration of inpatient stay estimated at 2.4 days for children aged 0-4 years and 3.7 days for those aged 5-14 years. Children accounted for 31% of the inpatient costs attributable to asthma and that was estimated at 26 million pounds.
Toelle et al (1995) estimated the cost of childhood asthma to Australian families. For the group of children who had been admitted to hospital in the previous year, the mean annual cost was $ A 884.34.
1.1.2.2.2 Increased hospitalisation due to asthma Hospitalisation rates for childhood asthma have increased steadily over the past 20 years (Strachan and Anderson, 1992). Asthma remains the second most common cause (after chemotherapy) for admission to a paediatric hospital bed despite
14
extensive educational programs and an exponential increase in the sales of preventive drugs (Ordonez et al, 1998). The admission rate in Australia has doubled over the past two decades to a level of 589/ 100 000 per annum in children up to 19 years (Robertson, 1995). In 1995-96, asthma was the most common reason for hospital admission among children while across all ages it ranked seventh. Asthma is also one of the 10 most common reasons for seeing a GP (Media release, 1999).
Similar changes have been reported from the United Kingdom (Strachan and Anderson, 1992), New Zealand (Mitchell et al, 1990), the United States (Weiss and Wagner, 1990; Lin et al, 1999; Crater et al, 2001) and Canada (Senthilselvan, 1994; To et al, 1996). Malmstrom et al (2000) conducted a study on childhood asthma in Finland during the period of 1976 to 1995 and reported that hospital admission had increased 2.8 fold and showed greatest increase in the 0–4 years age group among both sexes but a significant reduction in the 10 – 14 years age group.
Among Asian countries, the trend of increasing asthma admissions was found in Taiwan between 1990 to 1998 with 2-4 year old children found at greatest risk of admission with asthma (Kao et al, 2001).
1.1.2.2.3 Reasons for increasing hospitalisation with asthma There are three principal explanations that have been proposed for an increase in hospital admissions: an increase in prevalence or severity of asthma in children (Anderson, 1989; Robertson, 1995; To et al, 1996); diagnostic transfer from other non-asthma respiratory conditions such as bronchitis (Robertson, 1995; Minkovitz,
15
1999); and a change in the pattern of management such as changes in admission criteria so that milder cases are now being admitted (Weitzman et al, 1992; Kun, 1993; Weiss and Budetti, 1993; To et al, 1996).
The increase in prevalence of asthma is a contributing factor, but does not fully account for the increase in hospital admissions. Bauman (1993) showed that while there has been a dramatic increase in the prevalence of asthma in Australia over two decades, the increase in hospital admission has been at a rate of 0.7 to 1.0 % per annum. The major increase in hospital admission rates occurred during the first of these two decades with little changes during the second decade when there was both subjective and objective evidence of a continuing increase in the prevalence of asthma (Peat et al, 1994; Robertson, 1995). Strachan and Anderson (1992) showed that the increase in hospital admissions was in excess of the increase in prevalence and pattern of severity. In New Zealand, the admission rate increased 10-fold in the 15 years from the mid 1960s to 1984 (Mitchell, 1985).
Reports of the contribution of diagnostic transfer to the reported increase in admission rates have been conflicting. A study of hospital admissions of children with asthma in Western Australia over the first two decades found that the increase in asthma admissions was accompanied by a similar decrease in admissions for other acute respiratory conditions which share a potential diagnostic overlap with asthma (Carmen & Landau, 1990). Carmen and Landau (1990) suggested that the increase in admission rate for asthma could be accounted for that diagnostic transfer. Kun et
16
al (1993) in a similar study in New South Wales also found a 98% increase in the number of hospital admission due to asthma but suggested that there was a real increase rather than a change in diagnostic labeling (Kun et al, 1993).
Anderson et al (1980) conducted a study in the South-west Thames region, UK over the period 1970 to 1978, to observe the trends in hospital care of acute asthma and found that the number of admissions for asthma in the 5-14 years age group had increased by about 167% and was caused partly by an increase in readmission rates. They reported increasing numbers of self-referrals followed by increasing number of hospital admissions with less severe asthma and a higher readmission rate than patients referred by general practitioners (Anderson et al, 1980).
Strachan & Anderson (1992) also reported a marked change in utilization of health care services. Over the 13 year period, they found that there were more than two fold increases in Emergency Department (ED) attendances with acute asthma and a corresponding 50% reduction in reporting to general practitioners. Greater use of the diagnosis of asthma and changing attitudes to the management of acute asthma may underlie the observed shift from general practitioner care to ED attendance.
A child with mild to moderate asthma who is managed in ED is far more likely to be admitted to hospital than the child being managed by the general practitioner (Robertson, 1995). Change in the structure of general practice in Australia from the traditional family practitioner to the less personal multiple doctor clinic may also result in shifting from general practice to hospital care (Robertson, 1995).
17
It is likely that the diagnostic transfer has occurred in the community rather than within the hospital that results in more children seeking management of acute attacks in a hospital ED than by a general practitioner. This change in health care utilization together with an increase in the prevalence of asthma would account for part of the increase reported in hospital admission rates due to asthma (Robertson, 1995).
1.1.2.2.4 Risk factors likely to be associated with increasing hospital admission The major risk factor associated with the increase in admissions with asthma is age. Previous studies have reported that the increase in asthma morbidity as well as admission in hospital occurs mainly in children aged four years and under (Anderson, 1989; Gergen & Weiss, 1990; Wilkins & Mao, 1993; Mitchell et al, 1994; Senthilselvan, 1995; Lin et al, 1999; Malmstrom et al, 2000; Kao et al, 2001).
Horwood et al (1991) reported that there had been a changing pattern of admissions with a downward trend in admission rates for school aged group children and a continuing upward trend in pre-school age group since mid 1980s in New Zealand. They suggested that it could be due to increased use of cromoglycate and inhaled steroids in older children. Their findings were also supported by an Ontario, Canada study, which observed declining admission rates among children 5 years and older in the early 1990 that may have been due to increased use of prophylaxis with cromoglycate and inhaled steroid (To et al, 1996).
18
Hospital admission rates are higher among boys than girls (Mitchell, 1984; Horwood et al, 1991; Skobeloff et al, 1992; Senthilselvan, 1995; Gurkan et al, 2000).
Lower socio-economic background is associated with increased risk of hospital admission. Mitchell & Cutler (1984) found the rate of admission was higher in Maori and Pacific Islander children than Europeans. Another study on Polynesian children found that multiple hospital admissions were more likely in Polynesian than European children and suggested this was related to poor medical management rather than genetic or socio-economic factors (Mitchell & Quested, 1988). EllisonLoschmann et al (2002) found that Maoris experienced more severe asthma and had a higher number of hospitalisations for asthma than non-Maoris.
In studies from the UK, both Ayres (1986) and Watson et al (1996) found that the admission rates were higher in Asians living in UK than non-Asians. They suspected that poor access to and lack of health care, poor asthma education due to language barriers, as well as non-compliance were the main reasons behind that. Another study conducted in West Midland, U.K also found that hospitalisation rates in 5-14 year old children were higher in blacks than whites (Gilthorpe et al, 1998).
Gergen & Weiss (1990) found that the increase in hospital admissions for asthma in children were 1.8 times more in blacks than for the white population. Lin et al (1999) found asthma hospitalisations in children in New York City were more in areas with a higher proportion of poverty, unemployment, poorly educated residents,
19
and African-American and Hispanic ethnic groups. Others conducting the same type of study in New York City had similar findings (Goodman et al, 1998; Claudio et al, 1999). Carter et al (2001) conducted a study on asthma hospitalisation trends in Charleston, South Carolina, in a predominantly poor black population and found asthma hospitalisation rates increased 20-fold in the black children between 1956 and 1997 in contrast to a 5-fold increase in the white children. Castro et al (2001), repeating from St Louis, Missouri, found that the risk of hospitalisation for children with asthma was 8.4 (95% CI 7.0 – 9.9) times greater in African-Americans of lower socioeconomic status than whites of higher socioeconomic status. In New South Wales, asthma admissions were higher in rural than the metropolitan areas (Rushworth & Rob, 1995). Williams et al (1997) conducted a study on hospitalisation trends of aboriginal and non-aboriginal children in Western Australia during the period 1988 to 1993, and found asthma was a more frequent cause of admissions of aboriginal than non-aboriginal children and hospitalisation rates were higher in rural than metropolitan areas.
Seasonal variation also has a significant influence on admissions. Seasonal variation including early autumn peaks in admissions have been reported in several studies done at Northern Hemisphere and respiratory infections, meteorological conditions such as fall in temperature, increased and sudden rainfall, low humidity and thunderstorms, and allergens including dust-mites have been implicated as possible precipitating factors (Knot et al, 1984; Hawker & Ayers, 1996; Newson et al, 1997). Rushworth & Rob (1995) also reported that seasonal factors influenced
20
asthma hospitalisation in Australia, as have others (Derrick, 1972; Harju et al, 1997; Kao et al, 2001). They found the highest levels of admission occurred in the autumn months, and suggested this might be the effect of increased exposure to viruses and allergens, particularly among children. Lister et al (2001) reported the outbreaks of asthma in February in New South Wales after return to school from the long summer break. Several other studies also reported a marked reduction in asthma admission during long summer school break followed by a sharp increase on return to school (Knot et al, 1984; Storr & Lenney, 1989; Johnston et al, 1996; Garty et al, 1998). These studies suggest that school holidays disrupt the transmission of viral infections (particularly rhinoviruses) that are strongly associated with most paediatric asthma attacks and admissions and the resumption of school probably synchronizes subsequent attacks in children (Lister et al, 2001). In the Lister study, the majority of admissions that occurred after children returned to school were in pre-school children.
1.1.2.2.5 Measures for decreasing inpatient stay 1.1.2.2.5.1 Preventing Admission Preventing hospital admission in mild cases of asthma will involve consideration of all aspects of asthma prevention, education, and ambulatory management (Numa & Oberklaid, 1991). A prospective study in Royal Children’s Hospital, Melbourne by South (1997) evaluated the changes in hospital admission rates, length of stay (LOS), bed use and unplanned readmission rates for children with acute exacerbations of asthma after the introduction of Casemix funding. At baseline, the
21
hospital admitted around 1800 children per year with acute asthma and the average length of stay was 64.5 hours. Following the introduction of casemix funding there was a sharp fall in length of stay for asthma to an average of 39 hours and this was accompanied by a fall in the number of admissions. Over the time there was no increase in the unplanned readmission rate (South, 1997). Adam et al (1997) in a telephone survey to 30 parents of children admitted with asthma under ‘Casemix’ funding found that 70% had been discharged within 49 hours of admission and that 90% of the parents responded positively about the reduced length of stay.
1.1.2.2.5.2 Short stay areas Children’s hospitals policies are already aimed at preventing ‘unnecessary’ admissions. Admission criteria tend to be stringent, transferring pressure from hospital beds to emergency staff and families (Brown & South, 1999). The use of an emergency based paediatric observation unit in Toronto was associated with a reduction in the hospitalisation rate for children with acute asthma (Gouin et al, 1997).
1.1.2.2.5.3 Emergency Department In the ED, the rapid and appropriate delivery of inhaled bronchodilator will be the first-line therapy. If a doctor can not see the patient immediately, it may be appropriate for nursing staff to administer bronchodilators early if a checklist of safety measures has been worked through (e.g., triage, and certainty of previous diagnosis).
22
The early administration of oral or intravenous steroid therapy has been shown to decrease length of stay and reduce the need for hospitalisation in children with acute asthma (Harris et al, 1987; Tal et al, 1990). Connett et al (1994) found that the children who received prednisolone and more intensive treatment with bronchodilators had significantly higher PEF at 4 hours and were associated with significantly increased likelihood of discharge. Other studies have also supported the use of steroids to decrease the need for inpatient treatment (Littenburg & Gluke, 1986; Storr et al, 1987). Hilliard et al (2000) reported that initial arterial oxygen saturation of 90% could be considered a minimum ‘safe’ level (Van Asperen et al, 2001).
141
Readmission for asthma is another outcome factor which may reflect asthma severity (Crane et al, 1992; Vollmer et al, 1994; Li et al, 1995), psychological comorbidity, adequacy of hospital and community health services and changes in practice or admission criteria (Rushworth & Rob, 1995; McCaul et al, 2000). Readmission for asthma has contributed substantially to the increasing hospital admission rate (Anderson, 1978), with up to half of all admissions for asthma representing repeat admissions (Storr et al, 1988). Twenty to fifty percent of children hospitalized for asthma are readmitted within the following year (Mitchell et al, 1994; Senthilselvan, 1995; Madge et al, 1997; Raymond et al, 1998; Wesseldine et al, 1999; Minkovitz et al, 1999).
Among the factors associated with readmission are previous admissions (Mitchell et al, 1994; Li et al, 1995; Madge et al, 1997; Crater et al, 2001), young age (Mitchell et al, 1994; To et al, 1996; Minkovitz et al, 1999), lack of follow-up by a paediatrician (Macarthur et al, 1996), lack of inhaled corticosteroid (Macarthur et al, 1996; Blais et al, 1998), and parents' perception of negative consequences of treatment (Raymond et al, 1998).
As for readmission, a repeat attendance to Emergency Department with asthma is also an outcome factor of importance. Acute asthma attacks are frequent causes of attendances at hospital Emergency Departments (EDs) (Garrett et al, 1988; Wakefield et al, 1997). Children who were repeat attenders were more likely to have been admitted to hospital in the previous year; and to have a lower level of parental confidence due to lack of knowledge about asthma management (O’Halloran &
142
Heaf, 1989; Wasilewski et al, 1996; Wakefield et al, 1997). Investigators from various studies attributed increased hospitalisations to a greater likelihood on the part of asthmatic patients to use hospital EDs as primary sources of care (Halfon & Newacheck, 1986; Mitchell, 1989; Richards, 1989; Gergen & Weiss, 1990). A child with mild to moderate asthma who is managed in ED is far more likely to be admitted to hospital than the child being managed at home by the general practitioner (Anderson et al, 1980; Robertson et al, 1995).
Asthma exacerbations also continue to be a major cause of visits to emergency departments (Ashkenazi, 1993). Contributions to the development and outcome of asthma exacerbations may be underestimation of background severity of asthma, delay in initiation of rescue therapy, and inappropriate treatment that includes overreliance of bronchodilators and underuse of preventers. Studies conducted worldwide on management of asthma in Emergency Departments have highlighted deficiencies such as inadequate assessment of asthma (O’Halloran & Heaf, 1989; Canny et al, 1989; Chidley et al, 1991; Barnett & Oberklaid, 1991; Dawson & Penna, 1992), failure to provide adequate treatment in EDs (Chidley et al, 1991; Barnett & Oberklaid, 1991; Jayasuria et al, 1993; Ashkenazi et al, 1993; Dale et al, 1995) and inadequacy of follow-up arrangements from ED (Canny et al, 1989; Barnett & Oberklaid, 1991; Smith & Strunk, 1999).
Several factors have been identified that may influence and possibly prevent admission and readmission of children to hospital and repeat attendances to EDs, which include appropriate preventive treatment by corticosteroid or sodium
143
cromoglycate (Bauman et al, 1992; Greenberger, 1996; Wennergren et al, 1996; Blais et al, 1998a; Adams et al, 2001; Suissa & Ernst, 2001), provision of an individualized written asthma action plan (Dales et al, 1992; Gillies et al, 1996; Anonymous, 1997; Comino & Henry, 2001; NAC, 2002), regular review by a physician (Dales et al, 1992; Gibson et al, 1999a; NAEPP, 2002; NAC, 2002) and an acceptable level of asthma knowledge (Fitzclarence & Henry, 1990; Gibson et al, 1995; Henry et al, 1995; Liu & Feekery, 2001).
Ordonez and colleagues (1998) suggested that many hospital admissions could be prevented if children and their parents were given an individualised written asthma action plan, had greater general knowledge of asthma, complied with their preventive treatment, commenced appropriate medication early during an asthma attack and sought local medical assistance early if their condition was not improving.
Lack of parental knowledge about asthma and lack of use of written asthma action plan during an emergency has been associated with increased admissions (Henry et al, 1995; Ordonez et al, 1998) and emergency department visits with asthma (Wasilewski et al, 1996; Wakefield et al, 1997). Barriers to adherence in areas such as taking medications, keeping follow-up appointments, and using written asthma action plans during emergencies have led to ineffective control of asthma in children (Leickly et al, 1998).
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Most asthma is episodic and only 5 to 10% of children have persistent asthma (Isles & Robertson, 1993; Ordonez et al, 1998; Warner et al, 1998; Halterman et al, 2000; NAC, 2002). Although the acute presentation may be in children with a background of poorly controlled disease, other children have background symptoms that are infrequent or less severe (Jayasuria et al, 1993). In this situation, preventer medication is not indicated but there remain opportunities to ensure that future acute exacerbations
are
treated
optimally.
Pharmacological
therapy
should
be
accompanied by asthma education and trigger reduction (Warman et al, 2001).
Various national and international asthma management guidelines emphasize the importance of patient education and self-management and recommend the use of written asthma action plan during exacerbations to reduce morbidity and health costs (NAEPP, 2002; NAC, 2002; CAMP, 1998; NAEPP, 1997; British Thoracic Society, 1997; GINA, 1995).
The National Asthma Campaign (NAC) in Australia was launched in 1990 to conduct public and professional educational activities on asthma and to disseminate the principles of a six-step asthma management plan (Woolcock et al, 1989). This plan recommends the use of preventer therapy for patients with moderate or severe asthma and use of a written asthma action plan during an emergency. Between 1990 and 1993, there were significant changes in asthma management – reductions in the use of inhaled bronchodilators and antibiotics, increased use of peak flow meters and asthma action plans (Comino et al, 1996).
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The Australian six step Asthma Management plan recommends: 1) assess asthma severity when the patient is stable, not during an attack; 2) achieve best lung function by treating with intensive asthma therapy; 3) maintain best lung function by avoiding trigger factors and inappropriate medication; 4) maintain best lung function by treating with least number and doses of medication to reduce the risk of adverse effects; 5) develop an individualised asthma action plan in simple form with instruction of increasing or decreasing medication at the time of exacerbations, when and how to gain rapid access to medical care; 6) educate the patients and families about triggering factors, use of medications, how to implement written action plan and emphasize the need for regular review (NAC, 2002).
Asthma education reduces the frequency and the cost of healthcare utilisation by children with asthma (Clark, 1986; Feldman, 1987). An evidence based study suggested that improvements in patient outcomes could be achieved through a comprehensive program that includes asthma education, a written self-management plan and regular review (Coughlan et al, 2000). Other studies also reported that asthma education and provision of written asthma action plan significantly reduced the number of emergency treatments, and reattendances to emergency departments as well as readmission to hospital with asthma (Charlton et al, 1994; Ronchetti et al, 1997; Madge et al, 1997; Wesseldine et al, 1999).
Although asthma education is an appealing concept, available evidence does not indicate that education without optimal medical management is helpful. However, in only 3 studies was there specific mention of optimising medical management (Lewis
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et al, 1984; Charlton et al, 1994; Madge et al, 1997) and all of these showed a beneficial overall response to education. In the remaining 8 studies (of which 5 had a positive outcome and 3 had a negative outcome), it is hard to determine whether the consistency of response to education reflects lack of standardisation of medical management or failure of the educational strategy. Also, there is a need to tailor the education to the needs of the individual and to coordinate the input from health professionals delivering care with those providing education (Gibson et al, 1999b; Thoonen et al, 2002). In one recent study, Stevens et al (2002) reported that they did not find any significant change in preschool children with asthma whose parents has received an educational package with a written guided self-management plan compared with those who had not. Also, Haby et al (2002a) in a recent Cochrane based meta-analysis of children who had attended to the emergency room with asthma found that asthma education to their parents or to them did not significantly reduce subsequent emergency department visits, hospital admissions or unscheduled doctor visits for asthma. Toelle & Ram (2002) in another Cochrane-based metaanalysis reported that there was no consistent evidence that provision of a written asthma action plan produce better patient outcomes in regular asthma management and /or during exacerbations. Similarly, Bernard-Bonnin et al (1995) concluded that asthma self-management programs did not seem to reduce asthma morbidity measures. Both the exacerbation and the self-management of asthma have critical behavioural components such as knowledge and skill in attack prevention and attack management, adherence to medication and other treatment regimens and judgements of what to do at the time of crisis (Kohler et al, 1996).
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The majority of asthma education programs are designed for use during an inpatient admission for acute exacerbations or in structured outpatient programs. Limited information is available on the effects of educational intervention in the emergency department setting (Donna et al, 1999). Bolton, 1991 stated that even limited education (information only) might be effective if initiated in the emergency department setting. Children who present to a hospital Emergency Department with asthma represent a subgroup of children with important risk factors for worse control, such as more severe disease, less established medical support, or poor understanding about asthma.
Children who are admitted to Sydney Children’s Hospital see a paediatrician and have access to the hospital asthma educator. On the other hand those who are discharged home from the Emergency Department after receiving acute management for asthma have had more limited opportunity for assessment and management of the background disease. Anecdotal evidence suggests that some of these children have had multiple presentations to the hospital, some do not have a regular general practitioner, some do not use a written asthma action plan, and some should be receiving preventer medications but are not.
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1.3 Hypotheses and aims to be tested We would like to test the hypotheses that: 1) it is safe to discharge children from hospital when they are stabilised on 3-hourly reliever therapy; 2) children discharged from hospital on regular preventer therapy, with a written asthma action plan, with arrangements for follow-up and after asthma education would be less likely to represent to ED with asthma and to be admitted to hospital over the next 12 months; 3) some children discharged from ED with asthma will have untreated asthma for background severity whereas others will have asthma that does not warrant preventer therapy; 4) asthma education by telephone will improve provision and use of a written asthma action plan, increase regular use of preventer therapy, increase parental asthma knowledge, increase parental quality of life and decrease asthma symptoms 6 months after discharge from ED. The aims of these studies were: 1) to determine whether discharge from hospital with asthma is appropriate when children were stabilised on 3-hourly rather than 4hourly bronchodilator; 2) to determine whether asthma education in hospital, arrangements for follow-up, a written asthma action plan and use of preventer medications decreases the risk of representation to the ED and readmission to hospital; 3) to describe the background severity and control of asthma in children who are discharged from ED with asthma; 4) to determine whether asthma education provided by telephone soon after discharge from ED with asthma improves asthma management and control.
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CHAPTER 2: Methods There were two major studies addressing aspects of asthma management, namely the retrospective in-patient study and the prospective ED presentation study. Each of these was subdivided in two different studies to address different research questions.
2.1 Retrospective in-patient study This study addressed two different research questions, namely: (1) Outcome evaluation of early discharge from hospital with asthma, and (2) Effect of asthma education and followup on readmission and representation to ED. The files of children who had been admitted with asthma to the wards and intensive care unit of Sydney Children’s Hospital at Randwick from 1st January 2000 to 31st December 2000 were analysed. Study design: Only children whose primary reason for admission to hospital was asthma were considered. Those admissions where asthma was secondary to other diseases such as bronchiolitis, pneumonia and cystic fibrosis were excluded. The names and medical record numbers of those children who had been admitted with asthma in Sydney Children’s Hospital in the year 2000 were collected from the Emergency Department Information System (EDIS) data-base (International Classification of Diseases Ninth Revision (ICD-9) 493, cross reference, admission). Medical records were collected from the Medical Record Department. The first step was to verify that the primary reason for each admission was acute severe asthma.
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2.1.1 Outcome evaluation of early discharge from hospital with asthma In this study we included all admission with asthma in the year 2000. If a child had more than one admission in the 12-month period, all admissions were selected; thus each admission represented an individual observation. For admission of children with asthma, Sydney Children’s Hospital at Randwick followed published guidelines (Henry et al, 1993a) which were based on physical findings such as level of consciousness, talking in sentences or phrases or words, cyanosis, heart rate, respiratory rate, pulsus paradoxus, breathlessness, chest wall indrawing, wheezing and oximetry. It was expected that children who required inhaled beta-agonist (salbutamol) more frequently than 3 to 4 hourly and steroids would be admitted. Normally, the criteria used to establish readiness for discharge were expected to be according to hospital guidelines, namely when they had reached 4 hourly salbutamol, oximetry in room air >93% and were judged to be clinically stable by the attending medical team.
The following information was extracted from each medical record: 1. Demographic variables: age, sex, date and time of admission and discharge. 2. Severity variables and variables related to in-patient treatment: whether first attack, admitted to Intensive Care Unit, oxygen supplementation, intravenous salbutamol, use of ipratropium bromide, use of prednisolone or other systemic corticosteroids, nebulised treatment to deliver bronchodilators. 3. Variables related to discharge: actual time of discharge, number of consecutive doses of salbutamol at three hourly intervals received up to the time of
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discharge, number of consecutive doses of salbutamol at four hourly intervals received up to the time of discharge. 4. Adverse outcomes: readmission to hospital within one week and one month of discharge, representation to the Emergency Department within one week and one month of discharge. We defined a time of potential discharge from hospital as being achieved when each of the followed occurred; •
No oxygen supplementation.
•
No intravenous fluid or therapy.
•
Had at least two doses of salbutamol at 3 hourly intervals and due for a third dose.
•
Time before 5:30 PM or after 7:30 AM.
Children who fulfilled these criteria at or before the actual time of discharge were classified as having achieved their theoretical "time ready for discharge" (TRD) [‘ACHIEVED’ group] while those who were discharged before they had fulfilled these criteria were classified as ‘DID NOT ACHIEVE’ group. Accordingly the following information was documented: (1) Whether or not the criteria for theoretical TRD were achieved and if so, the difference between the length of stay from the theoretical TRD and actual time of discharge. (2) The number of consecutive doses of salbutamol at three hourly intervals recorded up to the time of theoretical discharge and the number of
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consecutive doses of salbutamol at four hourly intervals up to the time of theoretical discharge.
OUTCOME We looked at variables related to adverse events after theoretical TRD, and considered the following as adverse events: •
When the child received salbutamol more frequently than 3- hourly after reaching the theoretical TRD, or,
•
When the child received oxygen supplementation after reaching the theoretical TRD.
In particular, we counted an adverse event when a child had received 2 consecutive doses of salbutamol at least three hourly intervals but was then changed to salbutamol more frequently than three hourly and/or received supplemental oxygen supplementation. As indicated above, children were regarded as eligible for discharge only between 7:30 AM and 5:30 PM.
Re-admission to hospital and representation to the Emergency Department Using the computerised medical information system, the number of representations to the Emergency Department of Sydney Children Hospital with asthma and subsequent re-admission to the wards and intensive care unit, were calculated for the children who were admitted with asthma in the year 2000.
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Data Management & Data Analysis Approximately one in 20 charts was reviewed initially and also a random check of 20 charts at the end, were conducted by Professor Henry to check the accuracy of data collection. Our data was analysed using SPSS WIN version 10. Statistical analyses were performed using Chi-squared tests to look at different variables comparing the ‘achieved’ and ‘did not achieved’ groups. A Mann-Whitney test compared the median age and Wilcoxon Signed Ranks test was used to compare length of stay to actual discharge and length of stay to theoretical discharge.
2.1.2 Asthma
Education
representation
to
and the
Follow-up Emergency
protect
against
Department
and
readmission to hospital
In this study, we followed the children for one year from the date of discharge from index admission to see whether there was readmission or representation with asthma in the ED or not. The first admission in the year 2000 with asthma was considered as the index admission.
We determined whether there was documentation in the patient's record or in a standardised discharge summary that a written asthma action plan had been provided, whether an asthma educator, doctor or nurse had provided asthma education to the parents and the child, whether a follow-up appointment was
154
organized with a general practitioner or paediatrician, and whether the discharge medication included a preventer (inhaled corticosteroids or sodium cromoglycate).
Other variables recorded were sex, age (calculated from date of birth and date of index admission), history of previous admissions, and history of intensive care unit (ICU) admissions.
Those who did not represent to the ED within 1 year of their discharge were categorised as 'Not represented' group. The children who represented to the ED with asthma within 1 year of discharge, were categorised either as ‘readmitted’ or ‘represented to ED without admission’.
Data Management & Data Analysis Each child was assigned to one of the three primary outcome groups; 'not represented', 'represented to ED without admission' and 'readmitted within 1 year of discharge'. Statistical analysis was conducted using SPSS WIN version 10. Differences between the groups were evaluated using cross-tabulation and χ2 tests for categorical dependent variables e.g. age, sex, preventer medications prescribed, written asthma action plan, asthma education, organized follow-up received at the time of discharge, previous admission and previous ICU admission. Two-sided tests were used and P values
