Hepatic encephalopathy is a common severe complication of liver cirrhosis that, however, so far is not considered as an indication for organ allocation to patients on the transplant waiting list. Multiple psychometric tests have been developed to detect hepatic encephalopathy. However, there is only rare data about the predictive value of psychometric test results regarding mortality in patients with liver cirrhosis. This retrospective analysis of prospective data determined the predictive value of the Inhibitory Control Test (ICT), the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), the Portosystemic Encephalopathy Syndrome-Test and the Critical Flicker Frequency (CFF) assessment in regard to mortality in patients on the waiting list for liver transplantation.
143 patients awaiting liver transplantation were included. They underwent a test battery including the Inhibitory Control Test, the Repeatable Battery for the Assessment of Neuropsychological Status, the Portosystemic Encephalopathy Syndrome-Test which provides the psychometric hepatic encephalopathy score (PHES) and the Critical Flicker Frequency assessment at study inclusion. The PHES was available for all patients (n = 143), the RBANS scores for n = 115, the ICT results for n = 99, and the CFF results for n = 136 patients. Basic characteristics (age, gender, underlying liver disease, accompanying diseases) and Model for End-stage Liver Disease (MELD) -Score at the time of study inclusion were documented. Follow-up was done for 5 years. Patients who either received a liver transplantation or dropped out of the study during the observation period were censored. The five-year survival rate was analyzed with the Kaplan-Meier curve.
Patients with abnormal PHES had a significantly higher mortality risk than patients with a normal PHES (P < 0.0001). Also patients with an abnormal RBANS result had a significantly higher risk to die than patients with a normal RBANS result (P = 0.018), but the difference was less significant compared to the PHES. Mortality risk did not significantly differ between patients with normal or abnormal CFF or ICT results. (CFF: P = 0.412; ICT: P = 0.202). In a binary logistic regression analysis the MELD-Score and diabetes were independent prognostic factors for mortality risk (MELD: P = 0.003; diabetes: P = 0.008). The MELD-Score turned out to have significant impact on the test results regarding the PHES (P < 0.0001), but not concerning the other tests (CFF: P = 0.903; RBANS: P = 0.065; ICT: P = 0.139).
An abnormal PHES result is an indicator for an increased mortality risk, though less predictive than the MELD-Score.