Body Mass Index, Comorbidities, and Ambulatory Care Visits: The REGARDS Study

Individuals with obesity have more ambulatory care usage than individuals with normal weight and overweight. There is limited information on whether this is consistent across provider specialties and whether comorbidities explain the associations.

Among REGARDS (Reasons for Geographic and Racial Differences in Stroke) cohort study participants with Medicare fee-for-service coverage (n=9648), we identified ambulatory visits over 5 years. We used marginalized zero-inflated Poisson models to calculate ratios of means by body mass index (BMI), adjusted for demographics and health behaviors, and inverse odds weighting to evaluate mediation by diabetes, hypertension, dyslipidemia, stroke, coronary heart disease, atrial fibrillation, heart failure, chronic kidney disease, depressive symptoms, cancer, arthritis, and sleep apnea. The mean age of participants was 71.7±7.3 years, 35.1% were Black individuals and 64.9% White individuals, and 51.1% were women. Participants had a mean of 37.8 total, 16.0 primary care, 3.4 cardiology, 1.9 orthopedics, 0.9 pulmonology, and 0.4 endocrinology visits. Compared with individuals with BMI 18.5 to <25 kg/m² (n=2613), participants with BMI ≥35 kg/m² (n=1259) had 23% (95% CI, 21%-24%) more ambulatory visits. Participants with BMI ≥35 kg/m² had 26% more primary care, 20% more cardiology, 74% more orthopedics, 62% more pulmonology, and 85% more endocrinology visits. Comorbidities partly explained associations with overall, primary care, and orthopedics visits (39%, 38%, and 15%, respectively) and largely explained associations with cardiology, pulmonology, and endocrinology visits.

Understanding which specialty visits are associated with higher BMI can help with workforce planning and allocation of resources.