Association of Diabetes, Comorbidities, and A1C With Functional Disability in Older Adults

OBJECTIVE To examine the relationship of diabetes and functional disability in older adults and the possible mediating roles of comorbidities and A1C. RESEARCH DESIGN AND METHODS We analyzed data from a nationally representative sample of 6,097 participants aged >or=60 years in the National Health and Nutrition Examination Survey, 1999-2006. Diabetes was defined by self-report. Disability was defined as difficulty performing a physical task. We evaluated disability by grouping 19 physical tasks into five functional groups: lower-extremity mobility (LEM), general physical activities (GPA), activities of daily living (ADL), instrumental activities of daily living (IADL), and leisure and social activities (LSA). RESULTS Older U.S. adults with diabetes had the greatest disability in GPA (prevalence 73.6% [95% CI 70.2-76.9]), followed by LEM (52.2% [48.5-55.9]), IADL (43.6% [40.1-47.2]), ADL (37.2% [33.1-41.3]), and LSA groups (33.8% [30.8-36.9]). Diabetes was associated with two to three times increased odds of disability across functional groups (all P < 0.05). Comorbidities, mostly cardiovascular disease and obesity, and poor glycemic control (A1C >or=8%) together explained up to 85% of the excess odds of disability associated with diabetes, whereas poor glycemic control alone explained only approximately 10% of the excess odds. Adjustment for comorbidities, A1C, and diabetes duration fully attenuated the associations of diabetes with disability in all functional groups (all P > 0.05). CONCLUSIONS Older adults with diabetes have a high prevalence of disabilities with variable associations attributable to comorbidities and A1C. Aggressive management of cardiovascular risk factors and obesity may significantly reduce the burden of disability in this population.