Zhang, Hongju

Introduction: Obesity is a growing global health problem associated with substantial morbidity and mortality. The risk of obesity on incident new-onset heart failure is controversial. The aim of this systematic review and meta-analysis was to explore the association between overweight, obesity and incident new-onset heart failure. Methods: We systematically searched MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, Scopus, and the Cochrane Central Register of Controlled Trials from database inception through April 2015. Prospective cohort studies were included if the studies reported hazard ratios (HRs) of the association between overweight or obesity and new-onset heart failure (HF) relative to individuals with normal weight. Data were extracted by one reviewer followed by independent screening and extraction of study characteristics and outcome data by two other reviewers. Conflicts were resolved through consensus. Random-effects meta-analyses were used to pool the hazard ratio from the included studies. Subgroup analyses were performed to explore the potential sources of heterogeneity. Results: Out of 1,865 retrieved articles, we identified 10 relevant studies. Median follow-up was 12 years with a total of 82,167 individuals and 4,570 total HF events. Compared to normal body weight (body mass index (BMI) <25 kg/m2), overweight (BMI 25-29.9 kg/m2) was associated with 27% higher risk of new-onset heart failure events (pooled HR, 1.27; 95% confidence intervals (95% CI): 1.15-1.41; p<0.001; I 2 = 0%) and obesity (BMI ≥30 kg/m2) was associated with a two-fold increased risk for new-onset heart failure events (pooled HR, 2.09; 95% CI, 1.68-2.60; p<0.001; I 2 = 67.8%). Conclusions: Compared with normal-weight individuals, both overweight and obesity were independently associated with significantly higher incidence of heart failure. These results highlight the need for better understanding of mechanisms of obesity and heart failure.