Refinement of Hy's Law using the Drug-Induced Liver Injury Network Database.

Abstract

BACKGROUND Hyman Zimmerman observed that hepatocellular (HC) drug-induced liver injury (DILI) with jaundice had a mortality rate of ≥10% (Hy's Law). Hy's Law does not specify the timing of liver tests nor the definition of HC DILI versus cholestatic or mixed (C/M) DILI. We aimed to assess the validity of Hy's Law in the prospective Drug-Induced Liver Injury Network (DILIN) cohort. METHODS Drugs with ≥10 confirmed DILI cases with jaundice were analyzed. Four permutations of Hy's Law were applied: R≥ 5 using initial (1) or peak (2) ALT, AST and Alk P levels, and the FDA associated criteria of ALT or AST ≥ 3x ULN with Alk P ≤ 2x ULN using initial (3) or peak values (4). Mortality was death or liver transplant adjudicated to be due to DILI. RESULTS Using initial R values, mortality was 11.1% for HC vs 2.0% for C/M (p<0.001); using peak R values, mortality was 10.3% vs 1.6% (p<0.001). Using FDA associated definition, mortality was 7.9% vs 3.9% (p=0.04) using initial values and 7.9% vs 3.0% (p=0.01) using peak values. Using initial R values, drugs that frequently caused HC injury generally had mortality rates ≥ 10%; while drugs that typically caused C/M injury all had rates <10%. Occasional agents that caused HC injury with jaundice were associated with low mortality. CONCLUSIONS Initial R values were the most reliable means of identifying Hy's Law cases. There were some drugs that caused HC injury with jaundice but with mortality rates <10%. Refinement of Hy's Law is warranted.