Development of a multivariable model for predicting exercise functional capacity after liver transplantation

Abstract

Introduction: The assessment of the functional exercise capacity by liver transplant recipients might allow identifying functional disabilities and proposing a personalized exercise model for this population. Objective: This study aimed to develop a population-specific, multivariable prediction model of the six-minute walk distance (6MWD) in liver transplant recipients. Methods: This cross-sectional study enrolled 70 participants (men/women: 47/23; age 53 ± 12 years; 32 ± 32 months after liver transplantation). Functional exercise capacity was assessed using the six-minute walk test, considering the total distance (6MWD) as the dependent variable. Demographic characteristics— sex, age, body mass index (BMI), current physical activity level (short-form International Physical Activity Questionnaire [IPAQ])—entered the model as demographic independent variables. Disease-specific markers—pre-transplant model end-stage liver disease (MELD), fatigue (Fatigue Severity Scale [FSS])—also entered the full model as independent variables. Results: Patients walked 421 ± 102 m and predicted values yielded a group-average of 421 ± 64 m. The full multivariable model was 6MWD = 514.998 − 2.319 × age years + 48.151 × Sex male = 1, female = 0 − 0.751 × BMI kg/m2 + 28.396 × IPAQ code − 2.443 × FSS + 0.406 × Time months − 0.785 × MELD (adjusted R2 = 0.329, SE of bias = 79 m), suggesting that both demographic and
disease-specific information partially determines functional exercise capacity. Conclusion: Better functional capacity as assessed by a higher 6MWD is associated with lower age, sex (men), lower BMI, higher physical activity, lower fatigue, and lower MELD in liver transplant recipients. The overall performance of the model shows excellent accuracy and moderate precision.