BACKGROUND AND AIMS Studies on differential effect of aspirin therapy on HCC risk across the spectrum of liver diseases are lacking. We investigated the association between aspirin use and risks of HCC, liver-associated death, and major bleeding in chronic hepatitis B (CHB) patients with or without cirrhosis.

APPROACH AND RESULTS We identified 329,635 eligible adults with CHB from 2007 through 2017, using the Korean National Health Insurance Service database, including patients who received aspirin for ≥90 consecutive days (n = 20,200) and patients who never received antiplatelet therapy (n = 309,435). Risks of HCC, liver-associated mortality, and major bleeding were estimated in a propensity-score-matched cohort (19,003 pairs), accounting for competing risks. With a median follow-up of 6.7 years, 10-year cumulative incidence of HCC was 9.5% in the aspirin-treated group and 11.3% in the untreated group (adjusted subdistribution hazard ratio [aSHR], 0.85; 95% CI, 0.78-0.92). However, among patients with cirrhosis (2479 pairs), an association of aspirin use with HCC risk was not evident (aSHR, 1.00; 95% CI, 0.85-1.18). Cirrhosis status had a significant effect on the association between aspirin use and HCC risk (p_interaction , n = 0.04). Aspirin use was also associated with lower liver-associated mortality (aSHR, 0.80; 95% CI, 0.71-0.90). Moreover, aspirin use was not associated with major bleeding risk (aSHR, 1.09; 95% CI, 0.99-1.21).

CONCLUSIONS Aspirin use was associated with reduced risks of HCC and liver-associated mortality in adults with CHB. Cirrhosis status had a substantial effect on the association between aspirin use and HCC risk.