Nonalcoholic fatty liver disease and the risk of clinical cardiovascular events: A systematic review and meta-analysis

Abstract Objective Numerous studies have assessed the association between Nonalcoholic fatty liver disease (NAFLD) and cardiovascular disease (CVD). However, results have been conflicting due to variability in definitions of NAFLD and ascertainment of CVD, often combining clinical and surrogate endpoints. We therefore systematically reviewed published literature to assess the association between NAFLD and clinical cardiovascular events (CVE) and performed a meta-analysis. Methods We searched PubMed, Medline, Cochrane, CINAHL, and Web of Science databases using terms “nonalcoholic fatty liver disease”, “nonalcoholic steatohepatitis”, “cardiovascular disease”, and their combinations to identify prospective studies published from inception through March 2016. Data from selected studies was extracted and meta-analysis was then performed using random effects model. Results A total of six studies with 25,837 patients (NAFLD: 5953; controls: 19,884) were included in the final analysis. Patients with NAFLD had a significantly higher risk of clinical CVE compared to controls (RR: 1.77; 95% CI: 1.26–2.48, p < 0.001). Exclusion sensitivity analysis did not alter the above results. The association remained consistent for subgroups with clinical coronary artery disease (RR: 2.26; 95% CI: 1.04–4.92, p < 0.001) and ischemic stroke (RR: 2.09; 95% CI: 1.46–2.98, p < 0.001). The risk of cardiovascular mortality was also increased in the NAFLD group (RR 1.46, 95% CI 1.31–1.64, p < 0.001). Conclusion NAFLD patients have a significantly higher risk for clinical CVE compared to those without. These results need to be confirmed in large prospective studies.