Original article
Pancreas, biliary tract, and liver
In Patients With Cirrhosis, Driving Simulator Performance Is Associated With Real-life Driving

https://doi.org/10.1016/j.cgh.2015.11.007Get rights and content

Background & Aims

Minimal hepatic encephalopathy (MHE) has been linked to higher real-life rates of automobile crashes and poor performance in driving simulation studies, but the link between driving simulator performance and real-life automobile crashes has not been clearly established. Furthermore, not all patients with MHE are unsafe drivers, but it is unclear how to distinguish them from unsafe drivers. We investigated the link between performance on driving simulators and real-life automobile accidents and traffic violations. We also aimed to identify features of unsafe drivers with cirrhosis and evaluated changes in simulated driving skills and MHE status after 1 year.

Methods

We performed a study of outpatients with cirrhosis (n = 205; median 55 years old; median model for end-stage liver disease score, 9.5; none with overt hepatic encephalopathy or alcohol or illicit drug use within previous 6 months) seen at the Virginia Commonwealth University and McGuire Veterans Administration Medical Center, from November 2008 through April 2014. All participants were given paper-pencil tests to diagnose MHE (98 had MHE; 48%), and 163 patients completed a standardized driving simulation. Data were collected on traffic violations and automobile accidents from the Virginia Department of Motor Vehicles and from participants’ self-assessments when they entered the study, and from 73 participants 1 year later. Participants also completed a questionnaire about alcohol use and cessation patterns. The driving simulator measured crashes, run-time, road center and edge excursions, and illegal turns during navigation; before and after each driving simulation session, patients were asked to rate their overall driving skills. Drivers were classified as safe or unsafe based on crashes and violations reported on official driving records; simulation results were compared with real-life driving records. Multivariable regression analyses of real-life crashes and violations was performed using data on demographics, cirrhosis details, MHE status, and alcohol cessation patterns, at baseline and at 1 year.

Results

Drivers categorized as unsafe had more crashes and made more illegal turns on the driving simulator than drivers categorized as safe; a higher proportion of subjects with MHE were categorized as unsafe drivers at baseline (16%) than subjects without MHE (7%; P = .02), and at 1-year follow-up (18% vs 0%; P = .02). Alcohol cessation within <1 year and illegal turns during simulator navigation tasks were associated with real-life automobile crashes and MHE in regression analysis; road edge excursions in the simulator were associated with real-life traffic violations. Personal assessment of driving skills improved after each simulation episode.

Conclusions

In a study of 205 patients with cirrhosis, we associated results from driving simulation tests with real-life driving records and MHE. Traffic safety counseling should focus on patients with cirrhosis who recently quit consuming alcohol and perform poorly on driving simulation.

Section snippets

Patients

In total, 205 patients with liver cirrhosis were prospectively enrolled after informed consent at Virginia Commonwealth University Medical Center between November 2008 and April 2014. The inclusion criteria were age 18–65 years, current car driver, no overt mental impairment (Mini-Mental Status Examination >25), and liver cirrhosis diagnosed by biopsy or unequivocal evidence of decompensation (history of ascites, variceal bleeding) or presence of cirrhosis/varices on radiologic examinations.

Results

Baseline characteristics of the 205 recruited subjects are shown in Table 1.

Discussion

In this largest-studied cirrhosis cohort, we found that MHE diagnosed using paper-pencil tests negatively impacts on simulated driving skills and is associated with more real-life crashes and traffic violations at baseline and at 1 year compared with those without MHE,9, 15 which was corroborated with traffic records. We found that these real-life crashes and traffic violations are also linked to impaired driving simulator performance that remained stable over a year’s follow-up. Furthermore,

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    Conflicts of interest The authors disclose no conflicts.

    Funding The project was partly supported by Veterans Administration Merit Review CX001076, by RO1AA020203 from the National Institute on Alcohol Abuse and Alcoholism, by grant RO1DK087913 from the National Institute of Diabetes and Digestive and Kidney Diseases, and by the McGuire Research Institute.

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