Serum zinc levels as predictors of covert hepatic encephalopathy in patients with liver cirrhosis.

Background: Covert hepatic encephalopathy (CHE) significantly impacts the quality of life and prognosis in patients with liver cirrhosis. This study aims to analyze the prevalence and risk factors of CHE to identify high-risk patients who would benefit from therapeutic interventions.

Methods: This single-center, retrospective observational study included 126 patients without a history of overt hepatic encephalopathy (OHE). CHE was defined as a score above the age-based cutoff value in the Stroop test. Factors associated with the occurrence of CHE and the subsequent development of OHE were evaluated.

Results: CHE was detected in 47 patients (37.3%). A multiple logistic regression analysis identified serum zinc levels (per + 1 µg/dL, odds ratio 0.95, P = 0.0007) as the only risk factor associated with CHE, with a cutoff value of 60 µg/dL (AUC 0.71, P = 0.0001). Neither blood ammonia levels nor liver function were predictive of CHE. During a median observation period of 211 days, OHE developed in 18 patients (14.3%). The administration of more than 20 mg of furosemide was identified as a risk factor for developing OHE (hazard ratio 23.52, P = 0.0207).

Conclusion: Cirrhotic patients with serum zinc levels below 60 µg/dL exhibit a high risk of developing CHE, regardless of blood ammonia levels. These patients face a significant risk of developing OHE. Therefore, early zinc supplementation is recommended for the prevention of OHE, particularly for those prescribed 20 mg or more of furosemide.