Presentation (CTI)

OBJECTIVES: Obesity is a complex, heterogeneous chronic disease associated with numerous comorbidities, substantial variation in clinical presentation, and diverse healthcare resource needs. Untreated obesity causes considerable direct and indirect costs on society. The high disease burden and complexity of obesity have intensified the need for evidence-based approaches to obesity care. In Finland, approximately one in four adults has obesity, representing one of the highest prevalence rates in Europe. Finnish nationwide health registers provide a unique opportunity to investigate obesity care by linking comprehensive longitudinal data on treatment outcomes, treatments, and healthcare utilization. The aim of the study was to assess the quality of registry data and its suitability for obesity research.
METHODS: Adult individuals with BMI ≥27 kg/m², a record of anti-obesity medication purchase, an obesity diagnosis (ICD-10 code E66), or bariatric surgery were identified from Finnish national registers between 2021 and 2025. For this cohort, information on primary and secondary care healthcare use, medication use, comorbidities, and socioeconomic status was collected from national registers covering 2016-2025. Baseline patient characteristics were described. Obesity identification pathways, including BMI measurements, ICD-10 E66 diagnoses, anti-obesity medication use, and bariatric surgery, were characterized. The BMI share among individuals receiving anti-obesity medication or undergoing bariatric surgery was assessed. In addition, the coverage of obesity-related clinical measurements and number of repeated measurements, including body weight and laboratory values (lipid profile, HbA1c, and liver enzymes), was evaluated.
RESULTS: The total cohort comprised approximately 1.2 million individuals, including 226,944 anti-obesity medication users and 6,700 individuals who had undergone bariatric surgery. Among adults living with T2D in the cohort, weight records were available for 40% of the population, and HbA1c measurements for 80%.
CONCLUSIONS: This nationwide longitudinal obesity dataset provides comprehensive coverage of adults living with obesity and associated comorbidities and captures obesity identification and treatment pathways.