Introduction: Individuals with diabetes often present with co-occurring chronic conditions (CC), or multimorbidity. We adopted a more expanded definition of multimorbidity that describes Complex multimorbidity (C-MM) as the occurrence/co-occurrence of CC, functional limitations (FL), and geriatric syndromes (GS). We aimed to describe C-MM in midlife and older adults with self-reported diabetes and identify the combinations of conditions constituting C-MM.

Methods: We conducted a cross-sectional study of respondents 50 years or older from the 2018 Health and Retirement Study. Conditions constituting C-MM were defined using self-reported CC, FL, and GS. We conducted Association Rule Mining to identify the most common combinations of conditions constituting C-MM among respondents with diabetes and by age and race.

Results: Of 15,636 respondents, 28.7% reported having diabetes. Nearly 66% of respondents with diabetes reported CC, FL, and GS, whereas only 1.7% had none, 9.8% had one condition, and 22.9% had 2 conditions constituting C-MM. More than half reported at least six conditions, including 22.1% with 10 or more conditions. The most common combinations of conditions included at least one CC, FL, and GS, regardless of stratification by age or race. However, there were no predominant combinations when stratifying by count of conditions constituting C-MM.

Discussion: Our findings indicate that FL and GS are highly prevalent in midlife and older adults with diabetes. This study highlighted the importance of characterizing MM in broader terms rather than limiting its definition to the co-occurrence of CC alone, and the heterogeneity of conditions for midlife and older adults with diabetes.