Association between metabolically healthy obesity and atrial fibrillation. a systematic review and meta-analysis of longitudinal studies

Introduction: Obesity is not a single diagnosis, and the association of ‘metabolically unhealthy’ obesity with cardiovascular disease is well-described. However, the relationship between metabolically healthy obesity (MHO) and atrial fibrillation (AF) is still debated. Objective: Our objective is to investigate the association between MHO and the risk of AF. Methods: A comprehensive search of databases, including PubMed, EMBASE, Web of Science, and the Cochrane Library regarding longitudinal studies of MHO and risk of AF was performed. Random effects were used to pool the effect estimates. Results: Nine cohort studies comprising 4,250,557 participants were included. The pooled results revealed that individuals with MHO were associated with a greater incidence of AF than those with a metabolically healthy normal weight (HR: 1.34, 95 % CI: 1.26 to 1.42) with moderate certainty according to the Grading of Recommendations Assessment, Development, and Evaluation assessment. Individuals with MHO were associated with a lower risk of AF compared with participants with metabolically unhealthy obesity (RR: 0.48, 95 % CI: 0.36 to 0.64). Individuals with MHO were not significantly associated with the risk of AF as compared to metabolically unhealthy normal weight (HR: 1.04, 95 % CI: 0.89 to 1.22). Conclusion: MHO is associated with a greater incidence of AF, highlighting the importance of weight reduction in individuals without metabolic disorders in reducing the risk of AF. Registration: PROSPERO - registration number CRD42023432195.