Factors affecting lower limb muscle strength and cardiopulmonary fitness after allogeneic hematopoietic stem cell transplantation

PURPOSE: The aim of this study is to clarify the factors affecting physical function after allogeneic hematopoietic stem cell transplantation (HSCT). METHODS: We retrospectively analyzed 88 patients (median age, 44.5 years) who received allogeneic HSCT. Leg extension torque and peak oxygen consumption (VO(2)) were evaluated before and after HSCT. Patient factors (age, sex, underlying diseases, hemoglobin, serum albumin, and Karnofsky performance status score before transplant) and transplant factors (conditioning regimen, days to neutrophil engraftment, grades of acute graft-versus-host disease [GVHD], infections, and the interval between pre- and post-evaluation) were collected via chart review, and were used for correlational and comparison analyses in order to identify the variables associated with reduced post-HSCT leg extension torque and peak VO(2). Stepwise multiple regression analyses for post-HSCT leg extension torque and post-HSCT peak VO(2) were performed using age, sex, and the related variables with a p value < 0.2 in the correlational and comparison analyses. RESULTS: Leg extension torque and peak VO(2) were significantly reduced after HSCT (p < 0.001). Pre-HSCT leg extension torque, grades of acute GVHD, age, and the interval between pre- and post-evaluation were identified as significant factors associated with reduced post-HSCT leg extension torque. However, none of these factors were significantly associated with reduced post-HSCT peak VO(2), and only its pre-transplant value was identified as a significant factor. CONCLUSIONS: These findings suggest that improvements in muscle strength and cardiopulmonary fitness before HSCT are crucial for maintaining post-treatment physical function, especially in elderly individuals with acute GVHD requiring a long-term stay in a protective environment.