Nonalcoholic fatty liver disease (NAFLD) is the most common cause of elevated liver enzymes in patients of developed countries. We determined the long-term clinical and histological courses of such patients. In a cohort study, 129 consecutively enrolled patients diagnosed with biopsyproven NAFLD were reevaluated. Survival and causes of death were compared with a matched reference population. Living NAFLD patients were offered repeat liver biopsy and clinical and biochemical investigation. Mean follow-up (SD) was 13.7 (1.3) years. Mortality was not increased in patients with steatosis. Survival of patients with nonalcoholic steatohepatitis (NASH) was reduced (P ‫؍‬ .01). These subjects more often died from cardiovascular (P ‫؍‬ .04) and liver-related (P ‫؍‬ .04) causes. Seven patients (5.4%) developed end-stage liver disease, including 3 patients with hepatocellular carcinoma. The absence of periportal fibrosis at baseline had a negative predictive value of 100% in predicting liver-related complications. At follow-up, 69 of 88 patients had diabetes or impaired glucose tolerance. Progression of liver fibrosis occurred in 41%. These subjects more often had a weight gain exceeding 5 kg (P ‫؍‬ .02), they were more insulin resistant (P ‫؍‬ .04), and they exhibited more pronounced hepatic fatty infiltration (P ‫؍‬ .03) at follow-up. In conclusion, NAFLD with elevated liver enzymes is associated with a clinically significant risk of developing end-stage liver disease. Survival is lower in patients with NASH. Most NAFLD patients will develop diabetes or impaired glucose tolerance in the long term. Progression of liver fibrosis is associated with more pronounced insulin resistance and significant weight gain. (HEPATOLOGY 2006;44:865-873.)

Background and rationale for the study: Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in the Western world, strongly associated with insulin resistance and the metabolic syndrome. Nonalcoholic steatohepatitis, i.e. fatty liver accompanied by necroinflammatory changes, is mostly defined by the NAFLD activity score (NAS). The aim of the current study was to determine disease-specific mortality in NAFLD, and evaluate the NAS and fibrosis stage as prognostic markers for overall and disease-specific mortality. Methods: In a cohort study, data from 229 well-characterized patients with biopsy-proven NAFLD were collected. Mean follow-up was 26.4 (± 5.6, range 6-33) years. A reference population was obtained from the National Registry of Population, and information on time and cause of death were obtained from the Registry of Causes of Death. Main results: NAFLD patients had an increased mortality compared with the reference population (HR 1.29, CI 1.04-1.59, p=0.020), with increased risk of cardiovascular disease (HR 1.55, CI 1.11-2.15, p=0.01), hepatocellular carcinoma (HR 6.55, CI 2.14-20.03, p=0.001), infectious disease (HR 2.71, CI 1.02-7.26, p=0.046), and cirrhosis (HR 3.2, CI 1.05-9.81, p=0.041). Overall mortality was not increased in patients with NAS 5-8 and fibrosis stage 0-2 (HR 1.41, CI 0.97-2.06, p=0.07), whereas patients with fibrosis stage 3-4, irrespective of NAS, had increased mortality (HR 3.3, CI 2.27-4.76, p<0.001). Conclusions: NAFLD patients have increased risk of death, with a high risk of death from cardiovascular disease and liver-related disease. The NAS was not able to predict overall mortality, whereas fibrosis stage predicted both overall and disease-specific mortality

Background Liver fibrosis is the most important predictor of mortality in nonalcoholic fatty liver disease (NAFLD). Quantitative risk of mortality by fibrosis stage has not been systematically evaluated. We aimed to quantify the fibrosis stage-specific risk of all-cause and liver-related mortality in NAFLD. Methods Through a systematic review and meta-analysis, we identified 5 adult NAFLD cohort studies reporting fibrosis stage specific mortality (0–4). Using fibrosis stage 0 as a reference population, fibrosis stage-specific mortality rate ratios (MRR) with 95% confidence intervals (CI), for all-cause and liver-related mortality, were estimated. The study is reported according to the PRISMA statement. Results 1,495 NAFLD patients with 17,452 patient years of follow-up were included. Compared to NAFLD patients with no fibrosis (stage 0), NAFLD patients with fibrosis were at an increased risk for all-cause mortality and this risk increased with increase in the stage of fibrosis: stage 1, MRR, 1.58 (95% CI 1.19–2.11); stage 2, MRR, 2.52 (95% CI 1.85–3.42); stage 3, MRR, 3.48 (95% CI 2.51–4.83), and stage 4, MRR, 6.40 (95% CI 4.11–9.95). The results were more pronounced as the risk of liver-related mortality increased exponentially with increase in the stage of fibrosis: stage 1, MRR, 1.41 (95% CI 0.17–11.95); stage 2, MRR, 9.57 (95% CI 1.67–54.93); stage 3, MRR, 16.69 (95% CI 2.92–95.36); and stage 4, MRR, 42.30 (95% CI 3.51–510.34). Limitations Inability to adjust for co-morbid conditions or demographics known to impact fibrosis progression in NAFLD, and the inclusion of patients with simple steatosis and NASH without fibrosis in the reference comparison group. Conclusion The risk of liver-related mortality increases exponentially with increase in fibrosis stage. These data have important implications in assessing utility of each stage and benefits of regression of fibrosis from one stage to another.

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In a systematic review and meta-analysis, Giovanni Musso and colleagues examine the association between non-alcoholic fatty liver disease and chronic kidney disease. Please see later in the article for the Editors' Summary