Global epidemiology of nonalcoholic fatty liver disease—Meta‐analytic assessment of prevalence, incidence, and outcomes

Abstract

Nonalcoholic fatty liver disease (NAFLD) is a major cause of liver disease worldwide. We estimated the global prevalence, incidence, progression, and outcomes of NAFLD and nonalcoholic steatohepatitis (NASH). PubMed/MEDLINE were searched from 1989 to 2015 for terms involving epidemiology and progression of NAFLD. Exclusions included selected groups (studies that exclusively enrolled morbidly obese or diabetics or pediatric) and no data on alcohol consumption or other liver diseases. Incidence of hepatocellular carcinoma (HCC), cirrhosis, overall mortality, and liver-related mortality were determined. NASH required histological diagnosis. All studies were reviewed by three independent investigators. Analysis was stratified by region, diagnostic technique, biopsy indication, and study population. We used random-effects models to provide point estimates (95% confidence interval [CI]) of prevalence, incidence, mortality and incidence rate ratios, and metaregression with subgroup analysis to account for heterogeneity. Of 729 studies, 86 were included with a sample size of 8,515,431 from 22 countries. . Fibrosis progression proportion, and mean annual rate of progression in NASH were 40.76% (95% CI: 34.69-47.13) and 0.09 (95% CI: 0.06-0.12). HCC incidence among NAFLD patients was 0.44 per 1,000 person-years (range, 0.29-0.66). Liver-specific mortality and overall mortality among NAFLD and NASH were 0.77 per 1,000 (range, 0.33-1.77) and 11.77 per 1,000 person-years (range, 7.10-19.53) and 15.44 per 1,000 (range, 11.72-20.34) and 25.56 per 1,000 person-years (range, 6.29-103.80). Incidence risk ratios for liver-specific and overall mortality for NAFLD were 1.94 (range, 1.28-2.92) and 1.05 (range, 0.70-1.56). Conclusions: As the global epidemic of obesity fuels metabolic conditions, the clinical and economic burden of NAFLD will become enormous. (HEPATOLOGY 2016;64:73-84)

Global burden of NAFLD and NASH: trends, predictions, risk factors and prevention

“…Again, these rates can be influenced by genetic predisposition, as described later. In summary, NAFLD prevalence rates differ by ethnicity within the USA 1,[18][19][20][21] . The Hispanic population has the highest prevalence whereas African Americans are reported to have the lowest prevalence, despite hav ing higher prevalence of hypertension and obesity, both NAFLD risk factors.…”

“…Nevertheless, there are indirect estimates for these rates, derived by calcu lating prevalence of NASH in NAFLD and preva lence of NAFLD in the general population. In this context, the prevalence of NASH among patients with NAFLD in the USA is reported to be 21% (95% CI 19.85-22.95%) 1 . Using this rate, prevalence of NASH in the US population is estimated to be around 3-4% 1 .…”

“…In this context, the prevalence of NASH among patients with NAFLD in the USA is reported to be 21% (95% CI 19.85-22.95%) 1 . Using this rate, prevalence of NASH in the US population is estimated to be around 3-4% 1 . The corres ponding prevalence of comorbid conditions associ ated with NASH in these individuals has been reported to be: obesity in 82%; type 2 diabetes mellitus (T2DM) in 48%; hyperlipidaemia in 82%; the metabolic syndrome in 76%; and hypertension in 70% 1 .…”

“…The preva lence of NAFLD in South America seems to be higher than the rate reported for the USA. Specifically, NAFLD prevalence (assessed by ultrasonography) for South America has been estimated to be ~30.45% (95% CI 22.74-39.4%) 1 . The majority of studies reporting the preva lence of NAFLD from South America have been performed in Brazil [15][16][17] .…”

Natural history of nonalcoholic fatty liver disease: A prospective follow‐up study with serial biopsies

“…Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease in the Western world, affecting up to 25% of the world's population1 and expected to rise in parallel with the epidemic of obesity. NAFLD is commonly associated with components of metabolic syndrome2 and is an independent risk factor for cardiovascular disease 3, 4…”