Covert hepatic encephalopathy: agreement and predictive validity of different indices

Abstract

Aim: To investigate the agreement and prognostic value of different measures of covert hepatic encephalopathy (CHE).

Methods: One-hundred-and-thirty-two cirrhotic outpatients underwent electroencephalography (EEG), paper-and-pencil psychometry (PHES) and critical flicker frequency, scored on the original/modified (CFFo/CFFm) thresholds. Eighty-four patients underwent Doppler-ultrasound to diagnose/exclude portal-systemic shunt. Seventy-nine were followed-up for 11 ± 7 mo in relation to the occurrence of hepatic encephalopathy (HE)-related hospitalisations.

Results: On the day of study, 36% had grade I HE, 42% abnormal EEG, 33% abnormal PHES and 31/21% abnormal CFFo/CFFm. Significant associations were observed between combinations of test abnormalities; however, agreement was poor (Cohen's κ < 0.4). The prevalence of EEG, PHES and CFFo/CFFm abnormalities was significantly higher in patients with grade I overt HE. The prevalence of EEG and CFFm abnormalities was higher in patients with shunt. The prevalence of EEG abnormalities was significantly higher in patients with a history of HE. During follow-up, 10 patients died, 10 were transplanted and 29 had HE-related hospitalisations. Grade I HE (P = 0.004), abnormal EEG (P = 0.008) and abnormal PHES (P = 0.04) at baseline all predicted the subsequent occurrence of HE; CFF did not.

Conclusion: CHE diagnosis probably requires a combination of clinical, neurophysiological and neuropsychological indices.

Keywords: Ammonia; Electroencephalography; Hepatic encephalopathy; Liver cirrhosis; Psychometry.

Figure 1

Cumulative hepatic encephalopathy-free survival. Cumulative hepatic encephalopathy (HE)-free survival over the follow-up period in relation to the combination of electroencephalographic (EEG) and clinical abnormalities (panel A, χ² = 8.2, P = 0.041) and the combination of psychometric hepatic encephalopathy score (PHES) and clinical abnormalities (panel B, χ² = 7.8, P = 0.050) at baseline.

Figure 2

Model for end-stage liver disease scores in patients. Model for end-stage liver disease scores (MELD) in patients grouped based on the combination of electroencephalographic (EEG) and clinical abnormalities (panel A) and the combination of psychometric hepatic encephalopathy score (PHES) and clinical abnormalities (panel B). ^aP < 0.05, ^bP < 0.01 vs post-hoc comparisons.