Matched Comparison Examining the Effect of Obesity on Clinical, Economic, and Humanistic Outcomes in Patients with Bipolar I Disorder.

Introduction: Bipolar I disorder (BD-I) is associated with an increased risk of obesity, but few studies have evaluated the real-world clinical, humanistic, and economic effects associated with obesity in people with BD-I.

Methods: This was a retrospective, cross-sectional analysis of responses to the 2016 and 2020 National Health and Wellness surveys. Respondents (18-64 years) with a self-reported physician diagnosis of BD-I were matched to controls without BD-I based on demographic and health characteristics. Respondents were categorized by body mass index as underweight/normal weight (< 25 kg/m), overweight (25 to < 30 kg/m), or obese (≥ 30 kg/m). Multivariable regression models were used to compare obesity-related comorbidities, healthcare resource utilization (HCRU), health-related quality of life (HRQoL), work productivity, and indirect and direct costs.

Results: Before matching, the BD-I cohort was younger than the non-BD-I cohort and included more female and white respondents and a greater proportion covered by Medicaid or Medicare. After matching, the BD-I and non-BD-I cohorts had similar characteristics. A total of 5418 respondents (BD-I, n = 1806; matched controls, n = 3612) were analyzed. Obese respondents with BD-I reported the highest adjusted prevalences of high blood pressure (50%), high cholesterol (35%), sleep apnea (27%), osteoarthritis (17%), type 2 diabetes (12%), and liver disease (4%). Obesity in respondents with BD-I was associated with the lowest HRQoL scores. Measures of work impairment were highest in respondents with BD-I and obesity, as was HCRU. Respondents with BD-I and obesity had the highest associated total indirect and direct medical costs ($25,849 and $44,482, respectively).

Conclusion: Obese respondents with BD-I had greater frequencies of obesity-related comorbidities, higher HCRU, lower HRQoL, greater work impairments, and higher indirect and direct medical costs. These findings highlight the real-world burden of obesity in people with BD-I and the importance of considering treatments that may reduce this burden.