Substance-use simulation impairs driving capability in patients with cirrhosis regardless of hepatic encephalopathy

Driving is independently affected by cirrhosis and hepatic encephalopathy (HE) and alcohol/substance use, but their concomitant impact is unclear. We aimed to determine the impact of alcohol and other substances on driving-simulator performance in cirrhosis with and without HE. Outpatients with cirrhosis and controls underwent cognitive testing and driving simulation for the following three conditions: baseline, wearing goggles simulating alcohol intoxication, and wearing goggles simulating opioid/benzodiazepine abuse. Outcomes were number of centerline crossings (CCs) and road-edge excursions (REEs). We compared controls versus patients with cirrhosis then subjects with cirrhosis with and without HE for all conditions, using generalized linear modeling (GLM). Sixty subjects (17 controls, 43 with cirrhosis [Model for End-Stage Liver Disease score, 10; 21 subjects with prior HE]) were included. Simulations showed higher CCs and REEs at baseline in patients with cirrhosis with and without HE versus controls. With alcohol- and substance abuse-impairment goggles, CCs increased but REEs decreased in cirrhosis. In the GLM, a time and group interaction was seen (p < 0.001) for CCs and REEs. Patients with cirrhosis showed higher CCs and REEs at baseline than controls (CCs, p = 0.003; REEs, p = 0.0001) and higher CCs (p = 0.03) and lower REEs (p = 0.001) with alcohol-simulating goggles. All groups were equally impaired with opioid/benzodiazepine-simulating goggles (CCs, p = 0.49; REEs, p = 0.46). Controls with alcohol-simulating goggles had similar CCs as the baseline of patients with cirrhosis (p = 0.98). conclusions: Simulating alcohol intake induces greater driving impairment in patients with cirrhosis versus controls, but similar patterns were seen with opioid/benzodiazepine-simulating goggles. At baseline, patients with cirrhosis have simulator outcomes equivalent to intoxicated controls. Driving simulation with goggles modeling substance abuse could improve insight into driving errors and enhance driving rehabilitation in patients with cirrhosis.