Multimorbidity and functional disability among older adults - the role of inflammation and glycemic status: An Observational Longitudinal Study.

INTRODUCTION: Specific multimorbidity combinations, in particular those including arthritis, stroke, and cognitive impairment, have been associated with high burden of ADL-IADL disability in older adults. The biologic underpinnings of these associations are still unclear.

METHODS: Observational longitudinal study using data from the Health & Retirement Study (N=8,618, mean age=74 years, 58% female, 25% non-White) and negative binomial regression models stratified by sex to evaluate the role of inflammatory and glycemic biomarkers (high-sensitivity C-reactive protein (hs-CRP) and HbA1c) in the association between specific multimorbidity combinations (grouped around one of eight index diseases: arthritis, cancer, cognitive impairment, diabetes, heart disease, hypertension, lung disease, and stroke; assessed between 2006-2014) and prospective ADL-IADL disability (2 years later, 2008-2016). Results were adjusted for sociodemographic characteristics, body-mass index, number of coexisting diseases, and baseline ADL-IADL score.

RESULTS: Multimorbidity combinations indexed by arthritis (IRR=1.1, 95%CI=1.01-1.20), diabetes (IRR=1.19, 95%CI=1.09-1.30), and cognitive impairment (IRR=1.11, 95%CI=1.01-1.23) among men, and diabetes-indexed multimorbidity combinations (IRR=1.07, 95%CI=1.01-1.14) among women were associated with higher ADL-IADL scores at increasing levels of HbA1c. Across higher levels of hs-CRP, multimorbidity combinations indexed by arthritis (IRR=1.06, 95%CI=1.02-1.11), hypertension (IRR=1.06, 95%CI=1.02-1.11), heart disease (IRR=1.06, 95%CI=1.01-1.12), and lung disease (IRR=1.14, 95%CI=1.07-1.23) were associated with higher ADL-IADL scores among women, while there were no significant associations among men.

DISCUSSION/CONCLUSION: The findings suggest potential for anti-inflammatory management among older women and optimal glycemic control among older men with these particular multimorbidity combinations as focus for therapeutic/preventive options for maintaining functional health.