The Association between Body Mass Index Groups and Metabolic Comorbidities with Healthcare and Medication Costs: A Nationwide Biobank and Registry Study in Finland

Background: The increasing prevalence of obesity imposes a significant cost burden on individuals and societies worldwide. Objective: In this nationally representative study, the association between body mass index (BMI) groups and the number of metabolic comorbidities (MetC) with total direct costs was investigated in the Finnish population. Study design, setting, and participants: The study cohort included 5,587 adults with BMI ≥ 18.5 kg/m² who participated in the cross-sectional FinHealth 2017 health examination survey conducted by the Finnish Institute for Health and Welfare. Data on healthcare resource utilization (HCRU) and drug purchases were collected from national healthcare and drug registers. Main outcome measure: The primary outcome was total direct costs (costs of primary and secondary HCRU and prescription medications). Results: Class I (BMI 30.0–34.9 kg/m²) and class II–III (BMI ≥ 35.0 kg/m²) obesity were associated with 43% and 40% higher age- and sex-adjusted direct costs, respectively, compared with normal weight, mainly driven by a steeply increased comorbidity in the higher BMI groups. In all BMI groups combined, individuals with ≥2 MetCs comprised 39% of the total study population and 60% of the total costs. Conclusion: To manage the cost burden of obesity, treatment should be given equal consideration as other chronic diseases, and BMIs ≥ 30.0 kg/m² should be considered in treatment decisions.