Plasma ammonia tied to death, hospitalization in cirrhosis patients

Among outpatients with clinically stable cirrhosis, higher levels of plasma ammonia appear to increase the risk of mortality and liver-related complications leading to hospitalization, a recent study has found.

Researchers enrolled 754 clinically stable outpatients (mean age 56 years, 66 percent men), in whom ammonia levels were measured and corrected to the upper limit of normal (AMM-ULN). The primary study endpoint was hospitalization with liver-related complications, which itself was a composite of new-onset or worsening ascites, overt hepatic encephalopathy, variceal bleeding, and bacterial infection.

Multivariable competing-risk frailty analysis showed that AMM-ULN was a significant predictor of liver-related complications, increasing such risk by more than twofold (hazard ratio [HR], 2.13, 95 percent confidence interval [CI], 1.89–2.49; p<0.001).

A similar effect was reported for mortality, though to a weaker magnitude (HR, 1.45, 95 percent CI, 1.20–1.76; p<0.001).

For 1-year liver-related complications, AMM-ULN yielded an area under the receiver operating characteristic curve of 77.9 percent, outperforming traditional predictive scores. Moreover, using 1.4 as the optimal cutoff, low and high AMM-ULN groups showed significant differences in mortality and liver-related complication event rates (p<0.001).

“We found that ammonia is a key determinant that helps to predict which patients will be hospitalized, develop liver-related complications, and die,” the researchers said, noting that further studies are needed to validate these findings before AMM-ULN can be integrated in routine clinical practice.