Ten-year progression of obesity-related complications in a population with overweight and obesity in the UK: A retrospective open cohort study.

Aim: To assess the prevalence of individual obesity-related complications (ORCs) and multimorbidity (≥ 1, ≥ 2 and ≥ 3 ORCs), and multimorbidity-associated healthcare costs, over 10 years.

Methods: This retrospective open cohort study used Discover, a UK database of linked primary and secondary electronic health records. Adults were stratified by body mass index (BMI; overweight: 25-< 30 kg/m; obesity class I: 30-< 35 kg/m; obesity class II: 35-< 40 kg/m; obesity class III: ≥ 40 kg/m). Outcomes by year since baseline were assessed for serial cross sections across the study period (1 January 2004 to 31 December 2019; the index date was the date of first eligible BMI measurement).

Results: Across 1 410 146 individuals (overweight: 1 008 101; obesity class I: 278 782; obesity class II: 80 621; obesity class III: 42 642), ORC prevalence was higher in successive BMI groups, and increases over time were generally greater for obesity relative to overweight. In those with ORC multimorbidity, both higher BMI and the presence of more ORCs were associated with higher annual per-person healthcare costs. Costs increased over time in those individuals with obesity and one or more ORC, as well as in those with obesity and two or more ORCs.

Conclusions: Higher BMI was associated with higher baseline ORC prevalence and a greater increase in ORC prevalence over time, and with higher healthcare costs in those with multimorbidity. To reduce the burden of overweight and obesity on patients and healthcare systems, the presence, number and type of ORCs should be considered in developing effective, targeted prevention and management care pathways.