Epidemiology/Health Services/Psychosocial Research B R I E F
R E P O R T
Diabetes in British Nursing and Residential Homes A pragmatic screening study TERENCE J. ASPRAY, MD1,2 KAREN NESBIT, RGN2 TIMOTHY P. CASSIDY, FRCP1
EMMA FARROW, MB, BS1 GILLIAN HAWTHORNE, FRCP2
n the U.K., 8 –10% of those ⬎65 years of age have diabetes (1), and more than a quarter of care-home residents may have the condition (2). Diabetes is often undiagnosed (2), and screening is recommended (3). However, the use of fasting glucose measurements alone has not been validated in the elderly population, and concerns have been expressed that results using this method are inconsistent in older people when compared with the oral glucose tolerance test (OGTT) (4). The aim of this study was to estimate the prevalence of diabetes and impaired fasting glucose (IFG) in a range of care-home types and to decide which tests were best for diagnostic screening: fasting capillary glucose, 2-h postprandial capillary glucose (PPG), or both.
method; Hemocue, Derbyshire, U.K.). Both fasting glucose and 2-h PPG were estimated. World Health Organization diagnostic criteria were followed: for impaired fasting glycemia (fasting glucose ⱖ100 mg/dl) and for diabetes (fasting glucose ⱖ110 mg/dl or random [in this case 2-h PPG] ⱖ200 mg/dl) (5). Recorded weight and blood pressure were documented. Subjects, carers, and family doctors were told the results as appropriate. A total of 1,630 residents were recruited, of whom 186 had previously diagnosed diabetes. Data on 111 subjects from six care homes screened during the pilot phase were not included in the final analysis, and 58 subjects refused to take part. Thus, at least one glucose measurement was obtained on 1,275 subjects: 86 had fasting glucose only, 212 had PPG only, and 977 had both. Statistical methods used included ANOVA, 2 goodness-of-fit test, and CIs, which were estimated using a desktop computer (Stata 6; StataCorp, College Station, TX). The local ethics committee approved the study.
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RESEARCH DESIGN AND METHODS — Newcastle upon Tyne has a population of ⬃260,000, of whom 3.5% have diabetes. There are 68 care homes in the city, comprising residential care homes offering 24-h social support and nursing homes offering additional nursing care. Residential and nursing homes for the elderly mentally infirm (EMI) provide specialist care for older adults with dementia. We recruited residents from all four types of care home. After consent/assent was obtained, all volunteers gave 200 l of capillary whole blood, for glucose estimation, using a glucose analyzer (glucose dehydrogenase
RESULTS Diabetes prevalence Results of screening are presented in Table 1 by care-home type. Diabetes (P ⫽ 0.005) but not IFG was more common in EMI homes. Comparing residential care alone, diabetes was more common in EMI
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From the 1Institute for Health of the Elderly, University of Newcastle upon Tyne, Newcastle General Hospital, Newcastle upon Tyne, U.K.; and the 2Diabetes Centre, Newcastle Primary Care Trust, Newcastle General Hospital, Newcastle upon Tyne, U.K. Address correspondence and reprint requests to Dr. Terence Aspray, Institute for Ageing and Health, Newcastle University, c/o Sunderland Royal Hospital, Kayll Road, Sunderland, SR4 7TP, U.K. E-mail:
[email protected]. Received for publication 11 November 2005 and accepted in revised form 23 November 2005. Abbreviations: EMI, elderly mentally infirm; IFG, impaired fasting glucose; OGTT, oral glucose tolerance test; PPG, postprandial capillary glucose. A table elsewhere in this issue shows conventional and Syste`me International (SI) units and conversion factors for many substances. © 2006 by the American Diabetes Association. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
DIABETES CARE, VOLUME 29, NUMBER 3, MARCH 2006
homes (P ⫽ 0.001). For nursing homes, IFG was more common in EMI homes (P ⫽ 0.02). Differences remained after adjustment for age. Of l,275 subjects with at least one screening test, 105 had undiagnosed diabetes (prevalence of 8.2%). Thus, with 186 having previously diagnosed diabetes, 291 subjects with diabetes were found among 1,461 subjects, giving a diabetes prevalence of 19.9%. Performance of the screening tests Using the results of both fasting glucose and PPG measurements as gold standard in 977 subjects with both results, fasting glucose alone had a sensitivity of 71% and a negative predictive value of 97%. PPG had a sensitivity of 43% and a negative predictive value of 95%. Subjects with diabetes were 3.7 kg (95% CI 0.4 –7.0, P ⫽ 0.03) heavier than nondiabetic subjects. Mean weight was 56.5 kg for those with diagnostic PPG alone and 68.5 kg for those with diagnostic fasting glucose and PPG (difference of 12 kg; 95% CI 0.4 – 24.0, P ⫽ 0.04). The mean weight for those with raised fasting glucose alone was 63.1 kg. CONCLUSIONS — Screening for diabetes among care-home residents using PPG and fasting capillary glucose achieves excellent population coverage with a simple bedside test. Undiagnosed diabetes was common, especially in those with dementia, where it was seen in up to 13%. We acknowledge potential limitations in this study. Failure to fast could cause false-positive results. However, investigators arrived early at the homes, before subjects were out of bed, to ensure that fasting results are valid. Consumption of breakfast was encouraged but the carbohydrate load may not have raised PPG to diagnostic levels, resulting in underestimation of diabetes prevalence. Finally, although plasma glucose is now advocated for the diagnosis of diabetes (6), measuring capillary glucose optimized population coverage and diagnostic thresholds were those of the World Health Organization and American Diabetes Association at the time. 707
Diabetes screening in British nursing homes Table 1—Characteristics of residents screened by care-home type
All subjects n Female (%) Age (years) Weight (kg) Blood pressure (mmHg) Subjects with diabetes n (%) Female (%) Age (years) Weight (kg) Blood pressure (mmHg) Subjects with IFG n (%) Female (%) Age (years) Weight (kg) Blood pressure (mmHg)
Residential care homes
EMI residential care homes
Nursing care homes
EMI nursing care homes
430 75 85.3* 59.8 134/75
293 68 82.2 58.9 133/73
317 70 84.0 57.8 124/73*
235 69 82.3 57.2 133/77
25 (5.8) 80 84.9 62.8 127/76
38 (13)† 66 79.1 64.5 138/77
22 (6.9) 55 84.1 60.3 117/72‡
20 (8.5) 75 82.5 60.3 129/78
45 (10.5)§ 71 85.4 61.2 131/71
27 (9.2)§ 70 82.3 60.1 142/76
19 (6.0) 58 82.6 62.1 130/80
27 ( 11.5) 78 83.5 56.7 133/78
Data are means, unless otherwise indicated. Significance levels: *P ⬍ 0.001; †P ⬍ 0.005; ‡P ⬍ 0.05. §Includes three residential and two EMI residential subjects with IFG on fasting glucose but diabetes on PPG.
American Diabetes Association guidelines advocate fasting glucose for the routine diagnosis of diabetes (6), but PPG (using the threshold for casual glucose of 200 mg) increased pick up. There is a physiological basis for use of PPG particularly in the elderly (7). This is especially relevant for leaner diabetic subjects with possible failure of insulin release in response to a dietary load, whom we found less likely to have diagnostic fasting glucose alone levels. An OGTT would have been a gold standard, but poor adherence among frail elders has been observed (2), and screening may not have been completed with the added work and cost involved in using an OGTT. The interpretation of IFG found in this population is not clear, as the link to cardiovascular risk and progression to diabetes may be less robust in the elderly (8). We therefore believe that more research is required on the natural history of abnormal glucose tolerance in the elderly so that appropriate clinical advice might be offered.
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Finally, we found worryingly high rates of undiagnosed diabetes among care-home residents with dementia. Epidemiological evidence supports an association of diabetes with cognitive impairment (9,10), and the risk of diabetes with newer antipsychotic agents may also be relevant, as they are frequently prescribed in this group (11). In conclusion, ⬃20% of care-home residents were identified with diabetes (compared with 3.5% from the district diabetes register). For diabetes screening in this population, we recommend that fasting glucose be augmented by PPG estimation, particularly in the leaner elderly population. Targeted screening of elderly residents with dementia is also likely to identify the highest rates of undiagnosed diabetes.
References 1. Croxson SC, Burden AC, Bodington M, Botha JL: The prevalence of diabetes in elderly people. Diabet Med 8:28 –31, 1991
2. Sinclair AJ, Gadsby R, Penfold S, Croxson SC, Bayer AJ: Prevalence of diabetes in care home residents. Diabetes Care 24: 1066 –1068, 2001 3. British Diabetic Association: Guidelines of Practice for Residents with Diabetes in Care Homes. London, British Diabetic Association, 1999, p. 58 4. DECODE Study Group on behalf of the European Diabetes Epidemiology Study Group: Will new diagnostic criteria for diabetes mellitus change phenotype of patients with diabetes? Reanalysis of European epidemiological data. BMJ 317: 371–375, 1998 5. World Health Organization: Definition, diagnosis and classification of diabetes mellitus and its complications: report of a WHO consultation. Geneva, World Health Org., 1999 6. Genuth S, Alberti KG, Bennett P, Buse J, Defronzo R, Kahn R, Kitzmiller J, Knowler WC, Lebovitz H, Lernmark A, Nathan D, Palmer J, Rizza R, Saudek C, Shaw J, Steffes M, Stern M, Tuomilehto J, Zimmet P, the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus: Follow-up report on the diagnosis of diabetes mellitus (Review). Diabetes Care 26: 3160 –3167, 2003 7. Meneilly GS, Elliott T: Metabolic alterations in middle-aged and elderly obese patients with type 2 diabetes. Diabetes Care 22:112–118, 1999 8. Kanaya AM, Herrington D, Vittinghoff E, Lin F, Bittner V, Cauley JA, Hulley S, Barrett-Connor E: Impaired fasting glucose and cardiovascular outcomes in postmenopausalwomen with coronary heart disease. Ann Intern Med 142:813– 820, 2005 9. Gregg EW, Yaffe K, Cauley JA, Rolka DB, Blackwell TL, Narayan KM, Cummings SR: Is diabetes associated with cognitive impairment and cognitive decline among older women? Study of Osteoporotic Fractures Research Group. Arch Intern Med 160:174 –180, 2000 10. Sinclair AJ, Girling AJ, Bayer AJ: Cognitive dysfunction in older subjects with diabetes mellitus: impact on diabetes self-management and use of care services: All Wales Research into Elderly (AWARE) Study. Diabetes Res Clin Pract 50:203– 212, 2000 11. Lean ME, Pajonk FG: Patients on atypical antipsychotic drugs: another high risk group for type 2 diabetes. Diabetes Care 26:3200 –3201, 2003
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