Falls are common and associated with significant morbidity for persons with cirrhosis and hepatic encephalopathy. In order to intervene with targeted rehabilitation efforts to reduce and prevent falls, a better understanding of mechanisms underlying balance deficits is needed. To this end, unipedal stance time (UST) is a useful measure of balance as it requires the integration of sensory, neurocognitive, and muscular factors.
We prospectively enrolled 119 outpatients with cirrhosis and history of hepatic encephalopathy from the hepatology clinic at Michigan Medicine. The primary outcome was UST. Each patient was evaluated for demographic and clinical factors [Child Turcotte Pugh (CTP) class, MELD score], physical function (grip-strength and hip-strength using lateral plank time), neurocognitive factors [Numbers Connection Test (NCT) A and B, recognition reaction time accuracy - ability to catch or inhibit catching an instrumented stick under 'lights on' and 'lights off' conditions within 400 ms], and sensory factors (lower limb vibratory sensation and visual contrast). Falls self-efficacy, perceived ability to perform different tasks without falling, was also assessed. We evaluated bivariate Pearson correlations and developed a linear regression model to identify significant contributors to balance impairment.
Participants were 50% female, aged 62.9 + 7.3 years, 80% CTP A, 18% CTP B, 2% CTP C, with MELD 11 + 5. The mean UST was 12.7 + 9.9 seconds (median = 9.42 seconds, IQR = 19.26). In bivariate analyses, UST was most highly correlated with lateral plank time (r = 0.61), followed by recognition reaction time accuracy [total, percent correct in lights on, and in lights off conditions (r = 0.47, r = .36, r = .33)] and NCT A and B tests (each r = 0.27). In multivariable regression, 54% of variance in UST was explained by significant factors of plank time, recognition reaction time accuracy, falls self-efficacy, age, and CTP. Based on standardized beta coefficients, plank time, CTP of B or C, and recognition reaction time accuracy were the strongest predictors. For every second increase of plank time, UST increases by 0.26 seconds on average. If classified by CTP of B or C, UST decreases by 5.8 seconds. For each additional percent correct on recognition reaction time accuracy, UST increases by 0.12 seconds.
The strongest factors associated with diminished balance, as indicated by UST, in this high fall-risk cirrhosis population are hip strength, clinical disease severity, and neurocognitive capacity. These findings support a rehabilitation approach that targets strengthening as well as neurocognitive training to address balance impairment.