OBJECTIVES: Obesity or overweight is associated with diabetes, cardiovascular complications, cancer, and knee replacement surgery. This study aimed to estimate direct healthcare costs of obesity-related complications in Japanese patients.

METHODS: The IQVIA claims database, comprising insurer-based claims, member register and annual health check-ups, was used to obtain direct healthcare costs for entire patient journeys across different healthcare institutions. Patients having BMI ≥27.0 kg/m² with at least two weight-related comorbidities, or BMI ≥35.0 kg/m² with at least one weight-related comorbidity were identified from June 2016 to December 2020. Direct healthcare costs associated with monitoring and bariatric surgeries were estimated by accumulating medical fees associated with deliveries of the relevant services, while acute obesity-related events were estimated using a generalized gamma regression model. The cost was inflated to reflect April 2022 Japanese medical fee schedule and converted to US-dollar.

RESULTS:

A total of 23,593 patients were enrolled in the study. The majority (75.06%) were male and aged 45–64 years (74.11%), with a mean BMI of 30.8 kg/m². At baseline, the most prevalent condition was hypertension (78.20%), followed by type 2 diabetes (T2D) without microvascular complications (42.69%), nonalcoholic steatohepatitis (18.83%), and T2D with microvascular complications (10.43%). Of all obesity-related acute events, knee replacement was the most expensive procedure ($24,161), followed by fatal stroke ($16,959), unstable angina ($15,557), and myocardial infarction ($14,743). During the observation period, eight patients received bariatric surgery, and the mean costs of laparoscopic sleeve gastrectomy, preoperative stays (defined as 3 days), and postoperative management (1 year) were $26,000, $114, and $2,585, respectively.

CONCLUSIONS: The healthcare costs estimated in this study will help assess the economic burden of obesity in Japanese clinical settings, leading to providing real-world cost evidence in future value-based economic evaluations of an effective intervention for obesity.