Arthritis–diabetes comorbidity and functional recovery in older adults: a longitudinal cohort study using the Health and Retirement Study

Abstract

Abstract Background Arthritis and diabetes commonly coexist in older adults, but recovery after disability has received less attention than disability onset. We examined whether coexisting diabetes was associated with disability onset, functional recovery, state-specific transitions, and mortality among older adults with arthritis. Methods This longitudinal cohort study used biennial Health and Retirement Study data from 2000 to 2022. Consecutive interview pairs contributed person-wave observations for adults aged 65 years or older. Time-updated arthritis and diabetes status defined four exposure groups. Functional status was classified as complete independence, instrumental activities of daily living (IADL) limitation, or activities of daily living (ADL) disability. Pooled multinomial logistic models estimated standardized 2-year probabilities with participant-clustered robust covariance. The primary comparison was arthritis–diabetes comorbidity versus arthritis only. Results The disability-onset analysis included 69,075 person-waves from 17,540 participants, and the recovery analysis included 23,725 person-waves from 10,066 participants. Comorbidity was associated with a higher probability of incident disability (17.1% vs 15.8%; risk difference [RD], + 1.30 percentage points; 95% confidence interval [CI], + 0.41 to + 2.22). Recovery to complete independence was less likely with comorbidity (19.9% vs 23.3%; RD, -3.42 percentage points; 95% CI, -4.72 to -2.10). Among observations beginning with ADL disability, any functional improvement was also less likely (23.0% vs 27.7%; RD, -4.71 percentage points; 95% CI, -6.43 to -2.99). Conclusions Coexisting diabetes was associated with a modest increase in disability onset but clearer reductions in recovery and functional improvement, together with higher mortality, among older adults with arthritis. These findings emphasize functional prognosis after disability in addition to prevention of disability onset.