Prognostic Importance of Pretransplant Functional Capacity After Allogeneic Hematopoietic Cell Transplantation

Background. The purpose of this study was to investigate the prognostic importance of functional capacity in patients undergoing allogeneic hematopoietic cell transplantation (HCT) for hematological malignancies. Patients and Methods. Using a retrospective design, 407 patients completed a 6-minute walk distance (6MWD) test to assess functional capacity before HCT; 193 (47%) completed a 6MWD test after hospital discharge. Cox proportional hazards regression was used to estimate the risk of nonrelapse mortality (NRM) and overall survival (OS) according to the 6MWD category (<400mvs.>= 400 m) and the change in 6MWD (before HCT to discharge) with or without adjustment for Karnofsky performance status (KPS), age, and other prognostic markers. Results. Compared with <400 m, the unadjusted hazard ratio for NRM was 0.65 (95% confidence interval, 0.44-0.96) for a 6MWD >= 400 m. A 6MWD of >= 400 m provided incremental information on the prediction of NRM with adjustment for age (p = .032) but not KPS alone (p = .062) or adjustment for other prognostic markers (p = .099). A significant association was found between the 6MWD and OS (p = .027). A 6MWD of >= 400 m provided incremental information on the prediction of OS with adjustment for age (p = .032) but not for other prognostic markers (p > .05 for all). Patients presenting with a pre-HCT 6MWD of <400 m and experiencing a decline in 6MWD had the highest risk of NRM. Conclusion. The 6MWD is a significant univariate predictor of clinical outcomes but did not provide prognostic information beyond that of traditional prognostic markers in HCT.