The association between cirrhosis and driving performance is of particular clinical relevance because of the life-threatening safety issues both for the driver with cirrhosis and the general public. Study aims were to assess (i) driving competency through the use of an in-office computerized battery and on-road driving assessment (DriveABLE) and (ii) the association between minimal hepatic encephalopathy (MHE), in-office paper-pencil tools, and additional measures (e.g., frailty, depression, cognitive testing) with unsafe driving.
Patients were prospectively recruited from 2 tertiary care liver clinics. In-office tests and in-office and on-road assessments of driving competence were completed. The χ2 test and 1-way analysis of variance were used to analyze differences among those with and without MHE. Logistic regression was used to evaluate predictors of an indeterminate/fail result on the in-office computerized driving assessment battery (DriveABLE Cognitive Assessment Tool [DCAT]).
Eighty patients participated with a mean age of 57 years, 70% male, 75% Child-Pugh B/C, and 36% with a history of overt hepatic encephalopathy. Thirty percent met MHE criteria on both the psychometric hepatic encephalopathy score and the Stroop app tests. Only 2 patients (3%) were categorized as “unfit to drive” in the on-road driving test, one with MHE and the other without. Fifty-eight percent of the patients were scored as indeterminate/fail on the DCAT. This corresponded to a higher mean number of on-road driving errors (5.3 [SD 2.1] vs 4.2 [SD 1.6] in those who passed the DCAT, P = 0.01). Older age (odds ratio 1.3; confidence interval 1.1, 1.5; P = 0.001) and MHE by Stroop/psychometric hepatic encephalopathy score (odds ratio 11.0; confidence interval 2.3, 51.8; P = 0.002) were independently predictive of worse performance on the DCAT.
Worse performance in in-office testing was associated with worse scores on a computerized driving assessment battery and more on-road driving errors, but in-office tools were insufficient to predict on-road driving failures. A diagnosis of MHE should not be used alone to restrict driving in patients with cirrhosis. At-risk patients require on-road driving tests under the supervision of driving regulatory agencies. Future studies should continue to refine and evaluate in-office or at-home testing to predict driving performance.