Nonalcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD) are common causes of chronic liver disease. NAFLD is associated with obesity and metabolic syndrome whereas ALD is ...associated with excessive alcohol consumption. Both diseases can progress to cirrhosis, hepatocellular carcinoma, and liver-related death. A higher proportion of patients with NAFLD die from cardiovascular disorders than patients with ALD, whereas a higher proportion of patients with ALD die from liver disease. NAFLD and ALD each are associated with significant morbidity, impairment to health-related quality of life, and economic costs to society.
NAFLD is a leading cause of liver-related morbidity and mortality. We assessed the global and regional prevalence, incidence, and mortality of NAFLD using an in-depth meta-analytic approach.
PubMed ...and Ovid MEDLINE were searched for NAFLD population-based studies from 1990 to 2019 survey year (last published 2022) per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Meta-analysis was conducted using random-effects models. Bias risk assessment was per Joanna Briggs Institute. Of 2585 studies reviewed, 92 studies (N=9,361,716) met eligibility criteria. Across the study period (1990-2019), meta-analytic pooling of NAFLD prevalence estimates and ultrasound-defined NAFLD yielded an overall global prevalence of 30.05% (95% CI: 27.88%-32.32%) and 30.69% (28.4-33.09), respectively. Global NAFLD prevalence increased by +50.4% from 25.26% (21.59-29.33) in 1990-2006 to 38.00% (33.71-42.49) in 2016-2019 ( p <0.001); ultrasound-defined NAFLD prevalence increased by +38.7% from 25.16% (19.46-31.87) in 1990-2006 to 34.59% (29.05-40.57) ( p =0.029). The highest NAFLD prevalence was in Latin America 44.37% (30.66%-59.00%), then Middle East and North Africa (MENA) (36.53%, 28.63%-45.22%), South Asia (33.83%, 22.91%-46.79%), South-East Asia (33.07%, 18.99%-51.03%), North America (31.20%, 25.86%-37.08%), East Asia (29.71%, 25.96%-33.76%), Asia Pacific 28.02% (24.69%-31.60%), Western Europe 25.10% (20.55%-30.28%). Among the NAFLD cohort diagnosed without a liver biopsy, pooled mortality rate per 1000 PY was 12.60 (6.68-23.67) for all-cause mortality; 4.20 (1.34-7.05) for cardiac-specific mortality; 2.83 (0.78-4.88) for extrahepatic cancer-specific mortality; and 0.92 (0.00-2.21) for liver-specific mortality.
NAFLD global prevalence is 30% and increasing which requires urgent and comprehensive strategies to raise awareness and address all aspects of NAFLD on local, regional, and global levels.
Summary
Background
The prevalence of non‐alcoholic fatty liver disease (NAFLD) is increasing in parallel with obesity and type 2 diabetes.
Aim
To review the global epidemiology of NAFLD
Methods
We ...retrieved articles from PubMed using search terms of NAFLD, epidemiology, prevalence, incidence, and comorbidities.
Results
Over 250 articles were reviewed. In 2016, the global NAFLD prevalence was 25%; this increased to >30% in 2019. Prevalence in Asia, Latin America and Middle East‐North Africa (MENA) was 30.8%, 34.5% and 42.6%, respectively. Prevalence increased with age. Although prevalence was higher in men, prevalence in post‐menopausal women was similar. NAFLD prevalence was higher in certain subpopulations, especially among the obese and those with metabolic syndrome (MS). However, the prevalence of lean NAFLD was 11.2%. The global prevalence of non‐alcoholic steatohepatitis (NASH) is estimated between 2% and 6% in the general population. Approximately 7% of patients with NAFLD have advanced fibrosis; rates were between 21% and 50% among patients with NASH. Overall mortality related to NAFLD was 15–20 per 1000 person‐years, and increased substantially in patients with NASH, especially in those with components of MS. Recent data suggest mortality/morbidity from NAFLD is increasing globally but NAFLD awareness remains low among patients and healthcare providers.
Conclusions
NAFLD poses a global public health problem with a very high disease burden in Asia, MENA and Latin America. Research is needed to better quantify the full impact of NAFLD and to develop strategies to improve awareness and risk stratification.
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Nonalcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease with increasing prevalence, which can progress to cirrhosis and liver failure. Because of the obesity epidemic and ...increasing prevalence of metabolic syndrome, NAFLD and its progressive form, nonalcoholic steatohepatitis, are seen more commonly in different parts of the world. This article reviews the worldwide epidemiology of NAFLD and nonalcoholic steatohepatitis. The PubMed database was used to identify studies related to epidemiology of NAFLD in the adult population. It is estimated that the epidemic of obesity will continue to fuel the burden of NAFLD and its long-term complications.
Background & Aims Hepatitis C virus (HCV) infection has hepatic and extrahepatic manifestations with various costs and impairments to health-related quality of life (HRQL). We performed a ...meta-analysis to determine the prevalence of extrahepatic manifestations in patients with HCV infection, how these impair HRQL, and their costs. Methods We performed systematic reviews of the literature using MEDLINE, CINAHL, and the Cochrane Systematic Review Database, from 1996 through December 2014, to identify studies of the following extrahepatic manifestations of HCV infection: mixed cryoglobulinemia, chronic kidney or end-stage renal disease, type 2 diabetes, B-cell lymphoma, lichen planus, Sjögren’s syndrome, porphyria cutanea tarda, rheumatoid-like arthritis, or depression. We performed a separate meta-analysis for each condition to determine prevalence rates of extrahepatic manifestations of HCV infection and their effects on HRQL. We determined the annual costs (inpatient, outpatient, and pharmacy) associated with extrahepatic manifestations of HCV infection. Results In an analysis of data from 102 studies, we found the most common extrahepatic manifestations to be diabetes (in 15% of patients) and depression (in 25% of patients). HRQL data showed that HCV infection had negative effects on overall physical and mental health. Total direct medical costs of extrahepatic manifestations of HCV infection, in 2014 US dollars, were estimated to be $1506 million (range, $922 million–$2208 million in sensitivity analysis). Conclusions In a systematic review and meta-analysis we determined the prevalence, risks, and costs associated with extrahepatic manifestations of HCV infection. These estimates should be added to the liver-related burden of disease to obtain a more accurate assessment of the total burden of chronic HCV infection. Prospective, real-world studies are needed to increase our understanding of the total clinical and economic effects of HCV infection and treatment on patients and society.
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. Global prevalence of NAFLD is 25.24% (95% CI: 22.10‐28.65) with highest prevalence in the Middle East and South America and lowest in Africa. Metabolic comorbidities associated with NAFLD included obesity (51.34%; 95% CI: 41.38‐61.20), type 2 diabetes (22.51%; 95% CI: 17.92‐27.89), hyperlipidemia (69.16%; 95% CI: 49.91‐83.46%), hypertension (39.34%; 95% CI: 33.15‐45.88), and metabolic syndrome (42.54%; 95% CI: 30.06‐56.05). 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)
Given significant advances in treatment of viral hepatitis and the growing epidemic of obesity, the burden of the different types of liver diseases in the USA may be changing. Our aim was to assess ...the shift in the prevalence of different liver disease aetiologies in the USA over the past three decades.
National Health and Nutrition Examination Surveys (NHANES; cross-sectional 1988-1994 and 1999-2016) were used.
A total of 58 731 adults from NHANES (1988-2016) were included. Over the study period, the prevalence of chronic hepatitis B and alcoholic liver disease remained stable: 0.3%-0.4% and 0.8%-1.0%, respectively (p>0.05). The prevalence of chronic hepatitis C decreased nearly twofold: 1.6% in 1988-1994 to 0.9% in 2013-2016 (p=0.03). In contrast, the prevalence of non-alcoholic fatty liver disease (NAFLD; by US-Fatty Liver Index) increased from 20.0% (1988-1994) to 28.3% (1999-2004) to 33.2% (2009-2012) and 31.9% (2013-2016) (p<0.0001). Furthermore, steady increases were observed in the rates of obesity (22.2% in 1988-1994 to 31.0% in 1999-2004 to 38.9% in 2013-2016), type 2 diabetes mellitus (T2DM) (from 7.2% to 8.2% to 13.5% same years), insulin resistance and hypertension (all p<0.0001). Yearly trend analyses showed that the only LD with consistently increasing prevalence was NAFLD (trend p=0.01). Multivariable regression analysis showed that obesity (OR 10.4; 95% CI 9.5 to 11.3) and T2DM (OR 3.7; 95% CI 3.2 to 4.2) were the major independent predictors of NAFLD.
Over the past 30 years in the USA, NAFLD is the only liver disease with growing prevalence, synchronous with the increasing rates of obesity and T2DM.
Nonalcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease. There is uncertainty around the economic burden of NAFLD. We constructed a steady‐state prevalence model to ...quantify this burden in the United States and Europe. Five models were constructed to estimate the burden of NAFLD in the United States and four European countries. Models were built using a series of interlinked Markov chains, each representing age increments of the NAFLD and the general populations. Incidence and remission rates were calculated by calibrating against real‐world prevalence rates. The data were validated using a computerized disease model called DisMod II. NAFLD patients transitioned between nine health states (nonalcoholic fatty liver, nonalcoholic steatohepatitis NASH, NASH‐fibrosis, NASH‐compensated cirrhosis, NASH‐decompensated cirrhosis, hepatocellular carcinoma, liver transplantation, post‐liver transplant, and death). Transition probabilities were sourced from the literature and calibrated against real‐world data. Utilities were obtained from NAFLD patients using the Short Form‐6D. Costs were sourced from the literature and local fee schedules. In the United States, over 64 million people are projected to have NAFLD, with annual direct medical costs of about $103 billion ($1,613 per patient). In the Europe‐4 countries (Germany, France, Italy, and United Kingdom), there are ∼52 million people with NAFLD with an annual cost of about €35 billion (from €354 to €1,163 per patient). Costs are highest in patients aged 45‐65. The burden is significantly higher when societal costs are included. Conclusion: The analysis quantifies the enormity of the clinical and economic burdens of NAFLD, which will likely increase as the incidence of NAFLD continues to rise. (Hepatology 2016;64:1577‐1586)
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