Health-Related Quality of Life of Caregivers of ... - SAGE Journals

Original ARticle

Health-related Quality of Life of Caregivers of People with Parkinson’s Disease in Singapore Siok Bee Tan1,2, RN, MN, Allison F Williams2, PhD, FRCNA, MNSt, Meg E Morris2, PhD, FACP, Eng King Tan3, MBBS, FRCP (UK) Nursing Division, Singapore General Hospital, Singapore, Melbourne School of Health Sciences, The University of Melbourne, Australia 3 Department of Neurology, National Neuroscience Institute (Singapore General Hospital Campus), Singapore 1 2

Abstract Introduction: To investigate the health-related quality of life (HRQoL) of caregivers for people with Parkinson’s disease (PD) living in Singapore. Methods: A face-to-face survey was conducted with a cross-section of caregivers for people with PD. The caregivers were recruited from a PD clinic at an acute tertiary hospital in Singapore and from the members of the Singapore Parkinson’s Disease Society. HRQoL was quantified using the SF-36v2® Health Survey, an internationally validated multi-purpose short-form health survey. Results: Ninety-four caregivers completed the survey (a response rate of 57.3%). The respondents were all above 21 years old, with most falling in the 51 and >61 years age range. Seventy-four of the respondents (78.7%) were female. As a whole, the caregivers scored lower in all 6 health domains compared to the general population (adjusted for age, gender and ethnic group) in Singapore. The were significant differences for the “Role Physical” and the “Role Emotional” domains, at 3.9 and 3.3 respectively. Caregivers had a much lower mental component summary (-2.4) when compared to the physical component summary (-1.6). Conclusion: It is important to identify the factors that influence the HRQoL of caregivers so that policies can be developed to lower the burden of PD on caregivers. Assessing the well-being of caregivers may help to identify individuals at risk. The well-being of caregivers has the potential to influence quality of life of people with PD. Keywords: caregiver, chronic illness care, survey, well-being

Introduction Parkinson’s Disease (PD) is a chronic, gradual and progressive neurodegenerative disease. Many individuals with PD need the support of an informal caregiver1. Informal caregivers include kin and nonkin individuals who often have a long-term or lifelong commitment to the person with PD and who provide both functional (task-oriented) and affective (emotional) unpaid assistance to said person2. Family members are the major source of informal care for people with PD3–6. The prevalence of PD is higher for people aged 50 years and above7 and most caregivers are spouses for whom the added responsibility of caregiving can be a significant

issue. The responsibility of caregiving often falls upon a female spouse or an adult daughter 8. With effective caregiving, early hospitalisation and institutionalisation may be deferred, possibly improving the HRQoL of the people with PD 9 while decreasing associated health care costs 10 and the consumption of limited health-related resources 2. A qualitative study by Davey et al5 reported that caring for people with PD can sometimes negatively impact upon the physical, psychological and social well-being of caregivers. Another study suggested that managing caregiving and employment responsibilities can become more difficult when

Proceedings of Singapore Healthcare  Volume 19  Number 4  2010

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the caregiver’s health problems place additional demands on leisure time11. As PD is associated with progressive physical disability12 and cognitive impairment13, caregivers need to adapt to changes in symptoms14. Although a small number of studies have examined caregiving experiences in Singapore15–17, none has examined the well-being of PD caregivers. It is important to determine the impact of PD on the caregiver health-related quality of life (HRQoL) within the Singaporean context. Singapore comprises three principal cultures16 and the findings of international studies may not accurately reflect the experiences of Singaporean caregivers. HRQoL is a multidimensional measure derived by assessing physical, psychological and social attributes as well as overall life satisfaction18. This study sought to investigate the HRQoL of caregivers for people with PD living in Singapore. Methods Study Design Prior to commencing this research, ethical approval was obtained from the SingHealth Centralised Institutional Review Board (2008/122/A) and the Human Research Ethics Committee of The University of Melbourne, Australia (HREC 0719562). The research protocols were developed in compliance with the standards of the Australian National Medical Research Council19 and the Singapore Guideline for Good Clinical Practice 20. The identity of all participants was protected by coding.

a minimum of three hours of care per day for a minimum of 6 months. The criterion of spending three or more hours in daily caregiving for a minimum of six months demonstrated the commitment that caregiving entails and is consistent with a pilot study of PD caregivers conducted in the United States21. Potential participants were excluded if they did not understand spoken English. Caregivers who agreed to participate in the survey were briefed about the study by a trained research assistant (RA). After obtaining written informed consent, the RA arranged to administer the survey at a time and location that was convenient for each caregiver. The sample size was determined according to the number of participants needed to provide a statistical power analysis of the data obtained. According to Cohen22, an adequate test is determined by a study’s sample size, significance criterion (α), population effect size (ES) and statistical power. For this study, a sample size of 85 was required to detect a moderately strong relationship using a bivariate analysis (two tailed, α= .05, power of .80).

Data Collection A cross-sectional survey was conducted between April 2009 and March 2010. Participants were recruited from the Singapore General Hospital neurology specialist outpatient clinic (SOC). The SOC forms part of the neurology department, which is one of the 2 campuses of the National Neuroscience Institute. It serves as a principal treatment and follow-up facility for patients with movement disorders. As recruitment of caregivers was affected by the closure of the neurology specialist clinic during May 2009 as a consequence of H1N1 (an infection caused by influenza virus A), approval was obtained to amend the study protocol to allow additional participants to also be recruited from the Parkinson’s Disease Society of Singapore.

Instrument and Measures The structured questionnaire was administered in the form of a booklet containing QualityMetric’s SF-36v2® Health Survey23 and questions seeking demographic and health-related information. The SF-36v2® questionnaire is a generic health assessment tool that is widely used internationally and in Singapore24. The tool contains 36 validated items measuring perceptions of mental and physical health that reflect a person’s health status and well-being25. It measures perceived health in the areas of physical functioning (PF), role-physical (RP), bodily pain (BP), general health (GH), vitality (VT), social functioning (SF), role-emotional (RE), and mental health (MH). The scores in each domain range from 0–100, with higher scores indicating better perceived health18. The physical health summary (PCS) score is derived from the PF, RP, BP and GH subscales and the mental health summary (MCS) is obtained from the VT, SF, RE and MH subscales. SF-36v2® also has good reliability25 and Singapore normative data are available for noncaregiver comparisons24.

To meet the inclusion criteria, a respondent had to be above the age of 21 years, and be the unpaid primary caregiver of a care recipient diagnosed by a neurologist as having idiopathic PD, providing

An estimate of care recipient disease severity was obtained by asking the caregivers three questions: “Which sides of the body are affected by PD?”, “How is balance affected by PD?”, and “How is mobility

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HRQoL in PD Caregivers in Singapore

affected by PD?”. The responses to these questions were used to estimate the Hoehn and Yahr stage26 and determine disease severity. Statistical Analyses SF-36v2® data were entered and analysed using Predictive Analytics Software (PASW), Release Version 18.0.0 (© SPSS, Inc, 2001, Chicago, IL, www. spss.com). Ten items were recoded to derive the final item response values according to SF-36v2® Health Survey guidelines25. Jenkinson27 compared United Kingdom and United States (US) methods for weighting and scoring the SF-36v1 summary measures and concluded that weighting the PCS and MCS using the US algorithms provides more uniform analyses of datasets. Using specific algorithms for 10 countries, Ware et al28 reported a high degree of equivalence within each country when compared with the US algorithms. QualityMetric Health Outcomes™ Scoring Software 3.0 with 1998 US Norms was used to convert the Singapore population normative values24 from SF-36v1 to norm-based scores. Normbased scoring creates directly comparable scores across different SF-36 versions, including SF-36v2®. According to established standards, 2–3 points is defined as the minimally important difference for PCS, while 3 points is accepted as the minimally important difference for both MCS and the 8 health domain scores25. Results Demographics A final sample of 94 caregivers participated in the survey, representing a response rate of 57.3% (response rate based on caregivers approached by RA at both recruitment sites). There were 74 female (78.7%) caregivers, the majority of whom were Chinese 77 (81.9%), the others being Malay (n=7, 7.4%), Indian (n=5, 5.3%) or other races (n=5, 5.3%). The age of caregivers was measured categorically in groups ranging from >21 years to > 71 years; most caregivers were in the 51 to > 61 years of age range. Of the caregivers, 89.4% had more than seven years of formal education, 60 (63.8%) were employed either full- or part-time, 18 (19.1%) were homemakers, 11 (11.7%) were retirees and four (4.3%) had stopped working to provide caregiving. The caregivers had been engaged in caregiving for a mean of 5.9 years (SD=5.2) for a mean of eight hours per day (SD=7.0). Most of the caregivers were

the spouses (n=44, 46.8%) or adult daughters (n=29, 30.9%) of care recipients. Most caregivers lived with the care recipients (n=79, 84%) and 43 (45.7%) engaged the help of domestic helpers. In addition, 54 (60.6%) of the caregivers received assistance in caregiving from siblings (n=22, 37.9%), children (n=18, 40%), spouses (n=9, 15.5%) or others (n=9, 15.5%). The majority of the caregivers sought help only from family and friends (79.8%) and most had not had any caregiver education about caring for people with PD nor had they participated in any support groups (73.4%). The majority of care recipients were male (n=60, 63.8%). Only 6 care recipients were aged between 31 and 50 years; most were 51 years or older (n=88, 93.6%). The age at which the care recipients were diagnosed with PD ranged from 33 to 89 years (M=61.8, SD=11.8) and the mean duration of their PD was 6.9 years (SD=5.6). Sixty-seven care recipients (71.3%) were in Hoehn and Yahr (HY) Stage III or higher while functioning at their best. Eighty-four (89.3%) were in HY Stage III or higher when functioning at their worst. Their HY scores ranged from 1 to 5; the median score was 3.0 and the mean was 2.9 (SD=1.3). SF-36v2® Health Survey The caregivers’ mean (M) and standard deviation (SD) scores (range: 0-100 )_for each of the eight health domains for were as follows: Physical Functioning (M=80.3, SD=21.6), Role Physical (M=77.2, SD=24.9), Bodily Pain (M=77.2, SD=22.6), General Health (M=68.6, SD=20.3), Vitality (M=60.4, SD=21.7), Social Functioning (M=77.7, SD=23.7), Role Emotional (M=79.2, SD=24.5) and Mental Health (M=73.5, SD=17.3). The mean SF-36v1 domain-specific scores for Singapore populations with known ethnic, gender and age characteristics were computed from the SF-36 normative value calculator developed by the SingHealth Centre for Health Services Research based on a cross-sectional, community based study by Thumboo et al29. The SF-36 normative values of the Singapore population allowed for a direct comparison between the Singapore PD caregivers because the expected scores were adjusted for demographic characteristics24. The Singapore population normative values were calculated for 89 of the caregivers; 5 caregivers had to be excluded as they indicated that they were


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Fig. 1. HrQoL of Caregivers and the normative value of the general population in Singapore, matched by age, gender and ethnic group. NV=Singapore general population normal values, CG=Singapore caregivers of people with Parkinson’s disease, HRQoL=Health related quality of life, PF=Physical Functioning, RP=Role Physical, BP=Bodily Pain, GH=General Health, VT=Vitality, SF=Social Functioning, RE=Role Emotional, MH=Mental Health, PCS=Physical Component Summary, MCS=Mental Component Summary. Significant results in bold.

“Other Races” and the calculator only had data for the main ethnic groups (Chinese, Malay and Indian) in Singapore. The normative values of the Singapore population were converted into norm-based scores using the QualityMetric Health Outcomes™ Scoring Software 3 to provide directly comparable scores. As shown in Fig. 1, the surveyed caregivers scored lower in all eight health domains when compared with the Singapore general population, adjusted for age, gender and ethnic group. Minimally important differences were found for scores on the Role Physical and Emotional domains where the differences were 3.9 and 3.3 respectively. For the other domains, the differences in scores ranged from 0.1 to 2.8. The caregivers’ SF-36 scores were almost identical to the SF-36 normative values for the PF, GH, and MH domains although the caregiver MCS score was lower (-2.4) than the PCS score (-1.6). The HRQoL of Singapore PD caregivers was compared with the health domain scores for

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caregivers in 2 international studies (PD caregivers in Spain30 and for multiple sclerosis (MS) caregivers in the UK 31). Table 1 shows the norm-based health domain scores for the three groups. When compared to the PD caregivers in Spain, Singapore caregivers scored higher. Minimally important differences were found for scores on the PF, BP, GH and MH domains (with differences ranging from 3.4 to 8.5). When compared to MS caregivers in the UK, Singapore caregivers scored higher on VT where the minimally important difference was 3.5. Discussion Caregivers of people with PD had a lower perceived HRQoL, when compared to normative values for the Singapore general population24. The caregivers had reduced Role Physical and Role Emotional scores, which may reflect difficulties accommodating work or other activities of daily living into the demands of caregiving. Role Physical is a measure of physical health-related role limitations and Role Emotional assesses mental health-related role limitations. Differences in the Physical Functioning, General Health and Mental Health domains for the


HRQoL in PD Caregivers in Singapore Table 1. HrQol of Singaporean Caregivers and Caregivers in Spain and the UK. N

PF

RP

BP

GH

VT

SF

RE

MH

Singapore Caregivers

94

48.7

47.9

52.4

48.9

51.0

47.1

46.2

49.2

Spain Caregivers

80

45.3

48.5

46.4

44.5

49.1

47.2

46.0

40.7

UK Caregivers

257

50.0

48.7

49.8

47.2

47.5

46.3

48.2

46.4

Note: N=Sample size, HRQoL=Health related quality of life, PF=Physical Functioning, RP=Role Physical, BP=Bodily Pain, GH=General Health, VT=Vitality, SF= Social Functioning, RE=Role Emotional, MH=Mental Health.

caregivers and the general population were not significant even though the majority of the PD care recipients were moderately disabled. Previous research has shown that caregiving tasks increased markedly at this stage32. A Spanish study of PD caregivers reported that the psychological well-being of caregivers was one of the most important predictors of caregiver burden30. The Mental Component Score provides a measure of psychological well-being and in the present study, the MCS score for PD caregivers in Singapore was lower than for the general population. The lower MCS score may indicate that PD caregivers in Singapore experience substantial caregiver burden. As reported elsewhere, in assessing caregiver burden, it is important to obtain some measure of caregiver emotional and social distress as these factors are reported to affect perceived caregiver well-being33. The PD caregivers in the current study had higher HRQoL than reported for Spain30. However, the care recipients in our study had higher disease severity than the care recipients in the Spanish study. Although higher disease severity would be expected to result in caregivers reporting lower HRQoL, it is possible that differences in culture and healthcare systems might account for these disparate results. Another noticeable difference is that the Singaporean caregivers had the support of domestic helpers. In Singapore, domestic helpers are usually employed for household chores, child care or for care of the elderly and the sick35. Almost half of the caregivers in the present study were assisted by employed domestic helpers and respite from caregiving may provide a greater sense of vitality.

Although the caregivers in the current study may have overrated disease severity to highlight caregiver burden, a study of 275 patient-caregiver pairs in USA reported a high correlation between patient-generated and caregiver-generated scores for PD physical status34. This suggests the Hoehn and Yahr status of care recipients may be reliably obtained from caregivers. Compared with a larger study of MS caregivers in the UK31 , the PD caregivers in Singapore had a higher vitality score in the health domain. The caregivers in the UK study were caring for people with MS. Although PD and MS are progressive neurological chronic diseases, and they may require similar caregiver activities throughout the course of these diseases. Conclusion For this sample, HRQoL of caregivers was lower compared to the Singapore general population. Optimal caregiver well-being has the potential to improve quality of life for both care recipients and their caregivers. The burden of caregiving can become increasingly challenging as PD progresses and disability is more pronounced. Caregiver burden may be experienced at any stage of the disease and it could be useful for regular assessments to be done. The timely identification of caregivers at risk of sub-optimal well-being may facilitate the provision of early interventions that support their caregiving role. Acknowledging the importance of caregivers’ well-being might also enable people with PD to be cared for in their own homes, with psychosocial and economic benefits for Singapore36.


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Acknowledgements Most of all, we would like to thank all the caregivers that participated in this study. We also would like to acknowledge Ms Song Lin Kei (Research Assistant) and Dr Chan Yiong Huak (Statistician) for their assistance in this study. Special acknowledgement is also due to the The University of Melbourne for their support. A Singapore General Hospital Research Grant (SRF#143/08) was used to obtain the license for SF-36v2, scoring software, manuals and recruitment of a research assistant to collect data. References

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