Mortality Outcomes by Fibrosis Stage in Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-analysis

Background & Aims: Fibrosis is a key determinant of clinical outcomes in nonalcoholic fatty liver disease (NAFLD), but time-dependent risk of mortality has not been reported in previous meta-analyses. We performed an updated time-to-event meta-analysis to provide robust estimates for all-cause and liver-related mortality in biopsy-confirmed NAFLD with comparisons between fibrosis stages.

Methods: Medline and Embase databases were searched to include cohort studies reporting survival outcomes by fibrosis stage in biopsy-proven NAFLD. Survival estimates were pooled using reconstructed individual participant data. Conventional meta-analysis was conducted to pool adjusted hazard ratios (HRs) using DerSimonian and Laird random effects model.

Results: A total of 14 articles involving 17,301 patients with NAFLD were included. All-cause mortality at 1, 5, and 10 years for stage 0 to 2 fibrosis was 0.1%, 3.3%, and 7.7% vs 0.3%, 20.6%, and 41.5% for stage 4 fibrosis. Compared with stage 0 fibrosis, all-cause mortality increased with fibrosis stage: stage 2; HR, 1.46 (95% confidence interval [CI], 1.08-1.98), stage 3; HR, 1.96 (95% CI, 1.41-2.72), and stage 4; HR, 3.66 (95% CI, 2.65-5.05). Risk for liver-related mortality increased exponentially as fibrosis stage increased: stage 2; HR, 4.07 (95% CI, 1.44-11.5), stage 3; HR, 7.59 (95% CI, 2.80-20.5), and stage 4; HR, 15.1 (95% CI, 5.27-43.4). Stage 3 to 4 fibrosis had a higher all-cause (HR, 3.32) and liver-related mortality (HR, 10.40) compared with stage 0 to 2 fibrosis, whereas stage 4 fibrosis had higher all-cause (HR, 2.67; 95% CI, 1.47-4.83) and liver-related mortality (HR, 2.57; 95% CI, 1.22-5.42) vs stage 3 fibrosis.

Conclusions: Risk of all-cause and liver-related mortality increases substantially with fibrosis stage. These data have important implications for prognostication and trial design.