Comparison of the prognostic importance of diagnosed diabetes, co-morbidity and frailty in older people

Aims To compare the relative prognostic importance in older people of diagnosed diabetes, the number and severity of co-morbidities and frailty. Methods Two thousand three hundred and five people aged ≥ 70 years comprised the clinical examination cohort of the Canadian Study of Health and Aging. Frailty was defined as a score of ≥ 5 on a 7-point Clinical Frailty Scale. The cohort was followed for 5 years. Results Diabetes was more likely to be associated with medium-term mortality (adjusted hazard ratio (HR) 1.42; 95% confidence interval (CI) 1.20-1.69) than co-morbidity (HR 1.03; 95% CI 1.01-1.05). Frailty most strongly predicted death (HR 2.72; 95% CI 2.34-3.16). Frail older adults were 2.62 times (95% CI 1.36-5.06) more likely to have a complication of diabetes, independent of age, sex and number of years living with diabetes. People with diabetes were younger than those without (81.3 vs. 83.3 years) but a similar proportion were frail (42.2 vs.43.4%). The median life expectancy for frail older adults with diabetes was 23 months (95% CI 18-28 months). Conclusions In this cohort, the risk of mortality in older people was defined more precisely by a clinical measure of frailty than by diabetes or burden of co-morbidity. Those with diagnosed diabetes were younger than those without but had the same frailty status; diabetes can therefore be considered to increase 'biological age' by 2 years in those aged over 70 years. The limited life expectancy of frail older people with diabetes highlights the importance of recognizing frailty and supports the individualization of care in older people with diabetes.