Effect modification of hepatitis B viral load on the association between metabolic risk factors and hepatic steatosis

BACKGROUND: It is not clear if chronic hepatitis B (CHB) infection potentiates the severity of hepatic steatosis (HS) in patients with metabolic risk factors. We tested for the effect modification of hepatitis B viral load on the association between metabolic risk factors and HS. METHODS: In this retrospective cross-sectional study, we included adult subjects, who had non-cirrhotic nonalcoholic fatty liver disease and CHB infection with positive hepatitis B envelope antibody. We reported descriptive statistics, stratified by detectable and undetectable hepatitis B viral load, by Kruskal-Wallis Rank Sum Test and chi-square. We reported coefficients of two multivariate regression predicting odds of HS > stage 2, testing for interaction between metabolic risk factors and hepatitis B viral load. RESULTS: When controlled for age, sex, and hepatitis B treatment, the odds of HS > stage 2 increased significantly by 77% for each additional metabolic risk factor [odds ratio (OR) 1.77, 95% confidence interval (CI): 1.20–2.69, P=0.005]. The odds of HS > stage 2 was not associated with detectable hepatitis B viral load (OR 1.00, 95% CI: 0.83–1.19, P=0.986). The association between the odds of HS > stage 2 and metabolic risk factors did not significantly change as hepatitis B viral load increased [ratio of odds ratio (ROR) 1.01, 95% CI: 0.94–1.08, P=0.839]. CONCLUSIONS: Our study does not find evidence of effect modification of hepatitis B viral load on the association between metabolic risk factors and HS in non-cirrhotic and hepatitis B envelope antibody positive patients with CHB viral infection. It suggests that the odds of HS in CHB infected patients is affected by metabolic risk factors and not by hepatitis B viremia.