Co-occurring Mental Illness Increases Expenditures among Adults with Obesity and Chronic Physical Illness

Objectives: To compare medical expenditures between adults with obesity and PI to those with obesity, PI and MI.

Methods: Cross-sectional analysis of 2,825 adults aged over 21 with obesity from a nationally representative survey of households, the Medical Expenditure Panel Survey. Chronic physical illness (PI) consisted of self reported diabetes, heart disease, and hypertension and mental illness (MI) included schizophrenia, affective disorders and anxiety. Inpatient, outpatient, emergency room, pharmacy, other and total expenditures were the dependent variables. Chi-square tests, logistic regression on likelihood of use and ordinary least squares regression on logged expenditures among users were performed. All regressions adjusted for gender, race/ethnicity, age, martial status, region, education, employment, poverty status, health insurance, smoking and exercise and the complex survey design of the survey.

Results: Among adults with obesity and PI, 39% had MI. The average total expenditures for obese adults with PI and MI were $7,429; those with only PI were $6,759. Mean pharmacy expenditures were $2,431 and $1,806 respectively. After controlling for all independent variables, except for inpatient, all expenditures were higher for obese adults with MI and PI compared to obese adults only with PI. The probability of emergency room was higher among obese adults with PI and MI.

Discussion: Among individuals with obesity and chronic physical illness, expenditure burden by all type except inpatient is increased when mental illness is added. Our study findings suggest cost-savings efforts should target this group of patients for whom the medical care is challenging.