Use of six-minute walk test to measure functional capacity after liver transplantation

Abstract

Background. Functional impairment is common in people with chronic liver disease (CLD), and improvement is expected following liver transplantation (LT). The Six-Minute Walk Test (6MWT) is an objective measure of functional performance. Objective. The aims of this study were: (1) to evaluate the feasibility of 6MWT performance after LT, (2) to compare post-LT 6MWT performance over time between patients with and without CLD, (3) to determine when post-LT 6MWT performance approaches expected values, and (4) to investigate predictors of poor 6MWT performance. Methods. The 6MWT was performed by 162 consecutive ambulatory participants (50 healthy controls, 62 with CLD, 50 with LT). Sex, age, and body mass index were used to predict expected 6MWT performance. Chi-square testing, analysis of variance, and Pearson coefficients compared percentage of predicted 6-minute walk distance (%6MWD) across groups. Multivariable mixed models assessed predictors of improvement. Results. The participants’ mean age was 53.5 years (SD=13.0), 39.5% were female, and 39.1% were nonwhite. At 1-month post-LT, only 52% of all LT recipients met the inclusion criteria for 6MWT performance. Mean %6MWD values for female participants improved from 49.8 (SD=22.2) at 1 month post-LT to 90.6 (SD=12.8) at 1 year post-LT (P