Impact of weight loss on obesity-related complications and direct healthcare costs in Japan: A modelling study

Abstract

Aim

Body mass index (BMI) in Japan has increased over the past decades, leading to corresponding increases in the risks of complications such as type 2 diabetes (T2D). We modelled the impact of weight loss on the incidence of 10 specific complications and resulting healthcare costs in a Japanese cohort.

Materials and Methods

We adapted our value of weight loss simulation model to represent a cohort of 100,000 Japanese individuals aged 20–69 years with a BMI of 25–50 kg/m². Complication prevalence data were from the Medical Data Vision electronic health record database, and costs were identified using a targeted literature review and the IQVIA claims database. The impact of weight loss was modelled from 2024 to 2029.

Results

Total estimated direct medical costs associated with complications were 171.7 million US dollars (USD) or 25.6 billion Japanese yen (JPY) in 2024, projected to increase to 234.9 million USD (35.1 billion JPY) by 2029. A 10% or 15% lower weight across the population was estimated to be associated with a lower incidence of all complications, particularly sleep apnoea, T2D and hypertension. The resulting estimated cumulative cost reductions amounted to 34.6 million USD (5.2 billion JPY) for a 10% weight loss and 47.7 million USD (7.1 billion JPY) for a 15% weight loss over 5 years, largely arising from reductions in T2D.

Conclusions

Weight loss in the Japanese population has the potential to drive major reductions in healthcare costs via prevention of complications associated with higher BMI and consequent reductions in costs associated with these complications. Greater weight loss is likely to be associated with greater cost reductions. Our analysis highlights the importance of prompt weight management support for people living with obesity.