Estimating the hospitalisation burden of obesity in Europe: evidence from the European health interview survey (EHIS) wave 3

: BACKGROUND: Obesity represents a significant public health and economic challenge across Europe, driving an increased chronic disease burden and increased hospital utilisation. Despite this impact, cross-national evidence quantifying obesity’s hospitalisation burden remains sparse, and there is only a limited understanding of the potential cost savings achievable through obesity prevalence reduction. METHODS: We analysed European Health Interview Survey (EHIS) Wave 3 (2019) data, encompassing adults aged 18 years and older across eight countries (Belgium, the Netherlands, Germany, Luxembourg, Spain, Italy, Portugal and Denmark). Our primary outcome was the number of hospital nights in the preceding 12 months. We employed negative binomial regression models with zero-inflated specifications to estimate the associations between hospitalisation and body mass index (BMI), alongside sociodemographic, health and lifestyle factors. Simulations were used to project the impacts of a 1% obesity prevalence reduction on hospital expenditures. RESULTS: Compared to normal weight, obesity and underweight were strongly associated with increased hospital nights (IRR = 1.19 and 1.92, respectively), while pre-obesity showed no such association. Hospitalisation increased markedly with age, whereas higher education and income provided protective effects in this regard, reducing stays by 7% and 8%, respectively. Hypertension, diabetes and depressive symptoms substantially elevated hospital utilisation, while physical activity reduced it by 28%. Regional variation emerged, with Southern and Northern Europe reporting lower rates than Western Europe. A 1% obesity prevalence reduction would yield €4.27 billion in annual savings, representing 1.71% of combined hospital budgets. CONCLUSIONS: Obesity and underweight significantly increase hospitalisation across Europe, placing substantial strain on health systems. Preventive strategies that promote healthy weight, physical activity and mental health could markedly reduce hospital demand and generate major economic savings. Even modest reductions in obesity prevalence offer strong health and fiscal benefits, underscoring the importance of sustained investment in prevention-focused public health policies intended to increase equity and healthcare sustainability across European countries.