NASH/Liver Fibrosis Prevalence and Incidence of Nonliver Comorbidities among People with NAFLD and Incidence of NAFLD by Metabolic Comorbidities: Lessons from South Korea

Background: NAFLD incidence, NASH prevalence, NAFLD fibrosis prevalence, incidence of metabolic comorbidities, and mortality data in the NAFLD population remain limited. Aims: We used a meta-analytic approach to “stage” NAFLD among the Korean population. Methods: We searched PubMed, Embase, Cochrane Library, and KoreaMed from inception until June 29, 2019, and calculated pooled estimates via the random-effects model. Results: We screened 1,485 studies and analyzed 191 eligible studies: 179 (3,556,579 participants) for NAFLD prevalence and outcome analysis and 32 (1,089,785 participants) for NAFLD incidence analysis. NAFLD prevalence was 31.46% overall and 50–60% in those with metabolic risks. The incidence (per 1,000 person-years) of NAFLD was 42.8 overall and 70–77% in those with metabolic risk. The incidence (per 1,000 person-years) of new-onset T2DM, hypertension, cardiovascular disease, and chronic kidney disease was found to be 16.9, 47.9, 100.6, and 13.9, respectively. From biopsy data, 30.21% of the NAFLD population had moderate-to-severe steatosis (9 studies, 2,461 participants) and 52.27% had NASH (7 studies, 1,168 participants) and 85.41% had fibrosis Conclusions: The overall prevalence of NAFLD was 31.46% with an incidence rate of 42.8 per 1,000 person-years. NASH prevalence was 52% but