Understanding the socio-economic and health burden of obesity: a 10-year retrospective analysis of population-wide administrative healthcare data.

Obesity is a major contributor to chronic disease and multimorbidity, leading to progressively increasing clinical complexity across the life course. However, the relationship between obesity and overall clinical complexity remains insufficiently characterized, particularly at the population level, where territorial and socioeconomic inequalities should also be considered. In this review, we summarize the current evidence and complement it with an in-depth characterization of the demographic, socioeconomic, clinical, and healthcare utilization burden associated with obesity in a population of 8 million people in Catalonia, Spain. Beyond individual comorbidities, we examine multimorbidity using a comprehensive risk stratification measure and evaluate the impact of obesity on healthcare resource utilization and expenditure. Obesity was more prevalent among women and socioeconomically disadvantaged populations and followed a marked geographic deprivation gradient. Compared with a reference population standardized by age, sex, and socioeconomic status, individuals with obesity had a substantially greater multimorbidity burden, with 13% classified as high risk according to the AMG index versus 5% of the reference population. They also had greater healthcare utilization, including 4.5 additional primary care visits and 2.4 more prescribed medications per person annually. Mean annual healthcare expenditure reached €2,633 per person, representing a 108% increase compared with the reference population, while the total healthcare expenditure attributable to obesity was estimated at €2.1 billion in 2023. These findings underscore the substantial impact of obesity on multimorbidity, healthcare utilization, and healthcare expenditure, reinforcing the need for policies that address both obesity and its underlying socioeconomic determinants.