Health state utilities associated with weight loss: preferences of people with type 2 diabetes and obesity in Japan

Abstract

Aims

Health state utilities associated with weight change are needed for cost-utility analyses (CUAs) examining the value of treatments for type 2 diabetes and obesity. Previous studies have estimated the utility benefits associated with various amounts of weight reduction in the US and Europe, but preferences for weight change in Asian cultures may differ from these published values. The purpose of this study was to estimate utilities associated with reductions in body weight based on preferences of individuals with type 2 diabetes and obesity in Japan.

Methods

Health state vignettes represented type 2 diabetes with respondents’ own current weight and weight reductions of 2.5%, 5%, 7.5%, 10%, 12.5%, 15%, and 20%. Utilities were elicited in time trade-off interviews with a sample of respondents in Japan with type 2 diabetes and body mass index (BMI) ≥25 kg/m² (the cutoff for obesity in Japan).

Results

Analyses were conducted with data from 138 respondents (84.8% male; mean age = 58.0 years; mean BMI = 29.4 kg/m²) from all eight regions of Japan. Utility gains gradually increased with rising percentage of weight reductions ranging from 2.5% to 15%. Weight reductions of 2.5% to 15% resulted in utility increases of 0.013 to 0.048. The health state representing a 20% weight reduction yielded a wide range of preferences (mean utility increase of 0.044). Equations are recommended for estimating utility change based on any percentage of weight reduction (up to 20%) in Japanese people with type 2 diabetes and obesity.

Limitations

This study was conducted in a sample with limited representation of patients with BMI >35 kg/m² (n = 13) and relatively few women (n = 21).

Conclusion

Results may be used to provide inputs for CUAs examining the value of treatments that are associated with weight loss in patients with type 2 diabetes and obesity in Japan.

Keywords:

• Health state utilities
• time trade-off
• type 2 diabetes
• weight
• BMI
• cost-utility analysis

JEL Classification Codes:

• I12
• I1
• I
• I19

Declaration of financial/other relationships

LSM, KDS, TH, WM, and JI are employed by Evidera, which received funding support from Eli Lilly and Company to conduct this research. AY is an employee of Breeze/Autumn Research, which received funding support from Evidera to conduct this research. JR, RSN, and KSB are employed by and own stock or hold shares in Eli Lilly.

Author contributions

LSM, KDS, TH, WM, JR, RSN, and KSB designed the study; LSM, KDS, TH, WM, and AY conducted the study; LSM, KDS, TH, and JI wrote the manuscript; JR, RSN, WM, AY, and KSB provided edits and comments on the manuscript drafts; and all authors approved the final version for publication.

Acknowledgements

The authors would like to thank Ines Canada and Paula Gonzalez of Global Perspectives and Keiichi Seki, Nobuko Akiyama, Miaki Tajima, Moe Kikuchi, Kazumi Hori, Kyoko Sato, Reina Kougu, and Akane Betsui of Breeze for assistance with participant recruitment and utility interviews in Japan; Toshihiko Aranishi and Manaka Sato of Eli Lilly Japan K.K for protocol review; Robyn Cyr of Evidera for statistical programming; and Amara Tiebout of Evidera for editing and formatting support.

Data availability statement

Data are available upon reasonable request.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Previous presentations

A portion of these study results were presented at ISPOR US in Boston, MA (May 7 – 10, 2023). The citation is: Matza LS, Howell TA, Redig J, Stewart KD, Morris W, Sato M, Newson R, Yasui A, Boye KS. Health State Utilities Associated with Weight Loss in People with Type 2 Diabetes in Japan. Presented at ISPOR; May 7 – 10 2023.

Ethical approval

All participants provided informed consent prior to participation. Study procedures and materials were approved by an ethics committee in Japan (Research Institute of Healthcare Data Science [RIHDS] RI20210278).

Additional information

Funding

This work and the rapid track service fee were funded by Eli Lilly and Company. The authors had independence in decisions related to the study design, study conduct, interpretation of data, and manuscript content.