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

Area of Science:

• Medical research
• Public health
• Health services research

Background:

• Obesity is linked to increased ambulatory care usage compared to normal weight.
• Limited data exists on specialty-specific usage and the role of comorbidities.

Purpose of the Study:

• To investigate the association between body mass index (BMI) and ambulatory care visits across various provider specialties.
• To determine the extent to which comorbidities mediate these associations.

Main Methods:

• Analysis of Medicare fee-for-service data from the REGARDS cohort (n=9648).
• Utilized marginalized zero-inflated Poisson models to assess visit ratios by BMI.
• Inverse odds weighting was used to evaluate mediation by a range of common comorbidities.

Main Results:

• Participants with severe obesity (BMI ≥35 kg/m² ) had 23% more total ambulatory visits compared to normal weight individuals.
• Obesity was associated with significantly higher visits in primary care, cardiology, orthopedics, pulmonology, and endocrinology.
• Comorbidities explained a substantial portion of the increased visits, particularly for cardiology, pulmonology, and endocrinology.

Conclusions:

• Higher BMI is associated with increased utilization across multiple ambulatory care specialties.
• Understanding specialty-specific utilization patterns in obesity is crucial for healthcare workforce planning and resource allocation.