Association of Histologic Disease Activity With Progression of Nonalcoholic Fatty Liver Disease.

Importance: The histologic evolution of the full spectrum of nonalcoholic fatty liver disease (NAFLD) and factors associated with progression or regression remain to be definitively established.

Objective: To evaluate the histologic evolution of NAFLD and the factors associated with changes in disease severity over time.

Design, Setting, And Participants: A prospective cohort substudy from the Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN) NAFLD Database study, a noninterventional registry, was performed at 8 university medical research centers. Masked assessment of liver histologic specimens was performed, using a prespecified protocol to score individual biopsies. Participants included 446 adults with NAFLD enrolled in the NASH CRN Database studies between October 27, 2004, and September 13, 2013, who underwent 2 liver biopsies 1 or more year apart. Data analysis was performed from October 2016 to October 2018.

Main Outcomes And Measures: Progression and regression of fibrosis stage, using clinical, laboratory, and histologic findings, including the NAFLD activity score (NAS) (sum of scores for steatosis, lobular inflammation, and ballooning; range, 0-8, with 8 indicating more severe disease).

Results: A total of 446 adults (mean [SD] age, 47 [11] years; 294 [65.9%] women) with NAFLD (NAFL, 86 [19.3%]), borderline NASH (84 [18.8%]), and definite NASH (276 [61.9%]) were studied. Over a mean (SD) interval of 4.9 (2.8) years between biopsies, NAFL resolved in 11 patients (12.8%) and progressed to steatohepatitis in 36 patients (41.9%). Steatohepatitis resolved in 24 (28.6%) of the patients with borderline NASH and 61 (22.1%) of those with definite NASH. Fibrosis progression or regression by at least 1 stage occurred in 132 (30%) and 151 [34%] participants, respectively. Metabolic syndrome (20 [95%] vs 108 [72%]; P = .03), baseline NAS (mean [SD], 5.0 [1.4] vs 4.3 [1.6]; P = .005), and smaller reduction in NAS (-0.2 [2] vs -0.9 [2]; P < .001) were associated with progression to advanced (stage 3-4) fibrosis vs those without progression to stage 3 to 4 fibrosis. Fibrosis regression was associated with lower baseline insulin level (20 vs 33 μU/mL; P = .02) and decrease in all NAS components (steatosis grade -0.8 [0.1] vs -0.3 [0.9]; P < .001; lobular inflammation -0.5 [0.8] vs -0.2 [0.9]; P < .001; ballooning -0.7 [1.1] vs -0.1 [0.9]; P < .001). Only baseline aspartate aminotransferase (AST) levels were associated with fibrosis regression vs no change and progression vs no change on multivariable regression: baseline AST (regression: conditional odds ratio [cOR], 0.6 per 10 U/L AST; 95% CI, 0.4-0.7; P < .001; progression: cOR, 1.3; 95% CI, 1.1-1.5; P = .002). Changes in the AST level, alanine aminotransferase (ALT) level, and NAS were also associated with fibrosis regression and progression (ΔAST level: regression, cOR, 0.9; 95% CI, 0.6-1.2; P = .47; progression, cOR, 1.3; 95% CI, 1.0-1.6; P = .02; ΔALT level: regression, cOR, 0.7 per 10 U/L AST; 95% CI, 0.5-0.9; P = .002; progression, cOR, 1.0 per 10 U/L AST; 95% CI, 0.9-1.2; P = .93; ΔNAS: regression, cOR, 0.7; 95% CI, 0.6-0.9; P = .001; progression, cOR, 1.3; 95% CI, 1.1-1.5; P = .01).

Conclusions And Relevance: Improvement or worsening of disease activity may be associated with fibrosis regression or progression, respectively, in NAFLD.