Mendelian randomization: estimation of inpatient hospital costs attributable to obesity

Dick, K., Schneider, J. E., Briggs, A. , Lecomte, P., Regnier, S. A. and Lean, M. (2021) Mendelian randomization: estimation of inpatient hospital costs attributable to obesity. Health Economics Review, 11, 16. (doi: 10.1186/s13561-021-00314-2) (PMID:33990897) (PMCID:PMC8122556)

Abstract

Background: Mendelian Randomization is a type of instrumental variable (IV) analysis that uses inherited genetic variants as instruments to estimate causal effects attributable to genetic factors. This study aims to estimate the impact of obesity on annual inpatient healthcare costs in the UK using linked data from the UK Biobank and Hospital Episode Statistics (HES). Methods: UK Biobank data for 482,127 subjects was linked with HES inpatient admission records, and costs were assigned to episodes of care. A two-stage least squares (TSLS) IV model and a TSLS two-part cost model were compared to a naïve regression of inpatient healthcare costs on body mass index (BMI). Results: The naïve analysis of annual cost on continuous BMI predicted an annual cost of £21.61 [95% CI £20.33 – £22.89] greater cost per unit increase in BMI. The TSLS IV model predicted an annual cost of £14.36 [95% CI £0.31 – £28.42] greater cost per unit increase in BMI. Modelled with a binary obesity variable, the naïve analysis predicted that obese subjects incurred £205.53 [95% CI £191.45 – £219.60] greater costs than non-obese subjects. The TSLS model predicted a cost £201.58 [95% CI £4.32 – £398.84] greater for obese subjects compared to non-obese subjects. Conclusions: The IV models provide evidence for a causal relationship between obesity and higher inpatient healthcare costs. Compared to the naïve models, the binary IV model found a slightly smaller marginal effect of obesity, and the continuous IV model found a slightly smaller marginal effect of a single unit increase in BMI.

• Item Type: Articles
• Additional Information: This study was funded by Novartis AG and study results were not contingent on the sponsor’s approval or censorship of the manuscript.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Lean, Professor Michael and Briggs, Professor Andrew
• Authors: Dick, K., Schneider, J. E., Briggs, A., Lecomte, P., Regnier, S. A., and Lean, M.
• College/School: College of Medical Veterinary and Life Sciences > School of Health & Wellbeing > Health Economics and Health Technology Assessment; College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
• Journal Name: Health Economics Review
• Publisher: BioMed Central
• ISSN: 2191-1991
• ISSN (Online): 2191-1991
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Health Economics Review 11: 16
• Publisher Policy: Reproduced under a Creative Commons License