Body mass index and health care utilization in diabetic and nondiabetic individuals

Abstract

Background: Although controversial, most studies examining the relationship of body mass index (BMI) with mortality in diabetes suggest a paradox: the lowest risk category is above normal weight, versus normal weight in nondiabetic persons. One proposed explanation is greater morbidity of diabetes in normal weight persons. If this were so, it would suggest a health care utilization paradox in diabetes, paralleling the mortality paradox, yet no studies have examined this issue.

Objective: To compare the relationship of BMI with health care utilization in diabetic versus nondiabetic persons.

Design: Population-based cross-sectional study.

Subjects: Adults in the 2000-2011 Medical Expenditures Panel Surveys (N=120,389).

Measures: Total health care expenditures, hospital utilization (≥1 admission), and emergency department utilization (≥1 visit). BMI (kg/m) categories were: <20 (underweight); 20 to <25 (normal); 25 to <30 (overweight); 30 to <35 (obese); and ≥35 (severely obese). Adjustors were age, sex, race/ethnicity, income, health insurance, education, smoking, co-morbidity, urbanicity, region, and year.

Results: Among diabetic persons, adjusted mean total health care expenditures were significantly lower in obese versus normal weight persons ($1314, 95% confidence interval [CI], $513-$2115; P=0.001). By contrast, among nondiabetic persons, total expenditures were nonsignificantly higher in obese versus normal weight persons (-$229, 95% CI, -$460 to $2; P=0.052). Findings for hospital and emergency department utilization exhibited similar patterns.

Conclusions: Normal weight diabetic persons used substantially more health care than their overweight and obese counterparts, a difference not observed in nondiabetic persons. These differences support the plausibility of a BMI mortality paradox related to greater morbidity of diabetes in normal weight than in heavier persons.