OBJECTIVES: Medical spending on obesity and ORC exceeds $260 billion annually in the US alone, and 75% of adults with obesity live with multiple ORC. As the prevalence of obesity increases, so will the prevalence of ORC and their associated costs. Here we summarize estimates of direct medical costs among adults with obesity in the US, by obesity severity and by the presence of ORC.

METHODS: A systematic review was performed following PRISMA guidelines using Medline/EMBASE to identify published manuscripts (2012-2023) and conference abstracts (2021-2023). Data on all-cause, per-person, total direct medical costs among samples of adults with obesity were extracted. Data were synthesized by obesity severity and the presence of ORC, and a gaps analysis performed.

RESULTS: From 8,500 records, 12 studies presented costs by obesity severity and seven by the presence of ORC. Direct medical costs increased with increasing obesity severity. Compared to those of normal weight, costs among those with obesity ranged from 1.1- to 1.7-fold (obesity class I), 1.2- to 2.2-fold (obesity class II), and 1.2- to 3.3-fold (obesity class III), higher. Between-study differences in costs were driven by variation in age, year, inclusion of co-pays, and statistical analyses applied. Five studies focused on a single ORC, and one reported costs by the presence of multiple single comorbidities; individuals with comorbid arthritis, coronary heart disease, or myocardial infarction incurred higher costs. Another study characterized costs among those with multiple ORCs, and costs among those with obesity and T2DM, hypertension, and depression were 7 times higher than with obesity alone.

CONCLUSIONS: Direct medical costs in obesity are higher with increasing obesity severity and the development of ORC. Only one study identified here characterized the impact of multiple concurrent ORCs. Future studies are needed to help document and quantify the cost of comorbid ORC over time.