Homozygosity for rs738409:G in PNPLA3 is associated with increased mortality following an episode of severe alcoholic hepatitis

Abstract

Background & aims: Carriage of rs738409:G in PNPLA3 is associated with an increased risk of developing alcohol-related cirrhosis and has a significant negative effect on survival. Short-term mortality in patients with severe alcoholic hepatitis is high; drinking behaviour is a major determinant of outcome in survivors. The aim of this study was to determine whether carriage of rs738409:G has an additional detrimental effect on survival in this patient group.

Methods: Genotyping was undertaken in 898 cases with severe alcoholic hepatitis, recruited through the UK Steroids or Pentoxifylline for Alcoholic Hepatitis (STOPAH) trial, and 1188 White British/Irish alcohol dependent controls with no liver injury, recruited via University College London. Subsequent drinking behaviour was classified, in cases surviving ≥90days, as abstinent or drinking. The relationship between rs738409 genotype, drinking behaviour and survival was explored.

Results: The frequency of rs738409:G was significantly higher in cases than controls (29.5% vs. 18.9%; p=2.15×10^-15; odds ratio 1.80 [95% confidence interval (CI) 1.55-2.08]). Case-mortality at days 28, 90 and 450 was 16%, 25% and 41% respectively. There was no association between rs738409:G and 28-day mortality. Mortality in the 90 to 450-day period was higher in survivors who subsequently resumed drinking (hazard ratio [HR] 2.77, 95% CI 1.79-4.29; p<0.0001) and in individuals homozygous for rs738409:G (HR 1.69, 95% CI 1.02-2.81, p=0.04).

Conclusion: Homozygosity for rs738409:G in PNPLA3 confers significant additional risk of medium-term mortality in patients with severe alcoholic hepatitis. Rs738409 genotype may be taken into account when considering treatment options for these patients.

Lay summary: Individuals misusing alcohol who carry a particular variant of the gene PNPLA3 are more at risk of developing severe alcoholic hepatitis, a condition with a poor chance of survival. The longer-term outcome in people with this condition who survive the initial illness is strongly influenced by their ability to remain abstinent from alcohol. However, carriers of this gene variant are less likely to survive even if they are able to stop drinking completely. Knowing if someone carries this gene variant could influence the way in which they are managed. Clinical trial numbers: EudraCT reference number: 2009-013897-42; ISRCTN reference number: ISRCTN88782125.

Clinical trial numbers: EudraCT reference number: 2009-013897-42; ISRCTN reference number: ISRCTN88782125.

Keywords: Alcohol dependence; Genetic polymorphism, PNPLA3; Genotype; Hepatitis, alcoholic; Liver cirrhosis, alcoholic; Prednisolone; Prognostic scores; Risk allele; Survival.