Abstract
BACKGROUND: Cardiometabolic multimorbidity, defined as the coexistence of diabetes and heart disease, is increasingly common in older adults and is associated with adverse health outcomes. While individual conditions such as diabetes or heart disease have been linked to declines in physical function, little is known about how their coexistence affects objective physical performance measures over time. This study aimed to compare changes in gait speed and hand grip strength over five years among older adults with and without cardiometabolic multimorbidity and to identify factors associated with these declines. METHODS: We conducted a retrospective secondary analysis of the National Health and Aging Trends Study linked to Medicare administrative data from 2015 to 2019. Community-dwelling participants aged 66 years and older enrolled in Medicare fee-for-service were included. The participants were categorized into four groups: diabetes only, heart disease only, both conditions, or neither. Gait speed and hand grip strength were assessed annually over five years. Generalized estimating equation models were used to estimate changes in physical function, adjusting for demographics, clinical characteristics, and socioeconomic factors. RESULTS: The analytic sample included 4,351 participants. At baseline, older adults with both diabetes and heart disease presented significantly lower gait speed and hand grip strength than those with only one or neither condition. Over five years, the cardiometabolic multimorbidity group experienced the most pronounced declines. In fully adjusted models, cardiometabolic multimorbidity was associated with a decline in gait speed (β = -0.034, SE = 0.010) and hand grip strength (β = -0.048, SE = 0.015). Additionally, female sex (β = -0.049 for gait speed; β = -0.460 for hand grip strength), poorer self-rated health (β = -0.122 for gait speed; β = -0.061 for hand grip strength), and non-White race (β: -0.098 for African American and β : -0.055 for Others for gait speed;) were independently associated with steeper declines in physical function. CONCLUSION: Older adults with coexisting diabetes and heart disease experience accelerated declines in gait speed and hand grip strength compared with those with either condition alone or neither. These findings highlight the need for targeted functional monitoring and preventive interventions in this high-risk population, with particular attention given to sex, perceived health, and race-related disparities in physical aging.