Geographic and racial/ethnic variations in patterns of multimorbidity burden in patients with type 2 diabetes.

Background: Multimorbidity presents a significant public health challenge, but regional, rural/urban, and racial/ethnic differences in patterns of multimorbidity in diabetes are poorly understood.

Objective: To describe patterns of multimorbidity in medical and mental health by regional, rural/urban, and racial/ethnic variation in patients with type 2 diabetes mellitus.

Design: Retrospective cohort study from 2002 through 2006 PARTICIPANTS: A national cohort of 892,223 veterans with diabetes

Main Measures: Multimorbidity was the main outcome defined as: the measure of multimorbidity and two categorical outcomes, with pattern of medical and mental health comorbidities combined and separately.

Key Results: Among patients, 52% had 2+ comorbidities, 33% had a single comorbidity, and 14% had no comorbidity; 13.9% had both medical and mental health comorbidities, 70.3% had medical only, and 1.5% had mental health only. The odds of having 3+ comorbidities were nearly fourfold greater in patients 75 years and older relative to patients younger than 50 years (OR=3.95 [95% CI: 3.84, 4.06]). Compared to non-Hispanic whites, the odds of 3+ comorbidities among non-Hispanic blacks were 1.67 times greater (95% CI: 1.63, 1.71). Hispanics were more likely to have a mental health comorbidity alone (OR=1.20 [95% CI: 1.13, 1.28]) than non-Hispanic whites. For patients living in rural areas, the odds were higher of having 3+ comorbidities (OR=1.21 [95% CI: 1.19, 1.23]) and of having both medical and mental health comorbidities (OR=1.15 [95% CI: 1.13, 1.17]) compared to urban dwellers.

Conclusions: Among individuals with diabetes, traditionally disadvantaged groups, including non-Hispanic blacks and rural patients, appear to bear the greatest burden and risk of multimorbidity. Significantly greater odds with increasing number of comorbidities were seen by race/ethnicity, rural residence, and geographic region.