Determinants of functional performance in long-term survivors of allogeneic hematopoietic stem cell transplantation with chronic graft-versus-host disease (cGVHD)

This study examined factors accounting for functional performance limitations in 100 long-term survivors of allogeneic hematopoietic stem cell transplantation with chronic graft-versus-host disease (cGVHD). Functional performance, measured by the SF-36 physical component summary score, was substantially lower (mean = 36.8 +/- 10.7) than the US population norm of 50 (P < 0.001). The most severe decrements were in physical function (mean = 38.8 +/- 10.9) and physical role function (mean = 37.88 +/- 11.88); 68% of respondents exceeded the five-point threshold of minimum clinically important difference below the norm on these subscales. Controlling for age and gender, six variables explained 56% of the variance in functional performance: time since cGVHD diagnosis, cGVHD severity, intensity of immunosuppression, comorbidity, functional capacity (distance walked in 2min, grip strength, and range of motion), and cGVHD symptom bother (F = 11.26; P < 0.001). Significant independent predictors of impaired performance were intensive systemic immunosuppression, reduced capacity for ambulation, and greater cGVHD symptom bother (P < 0.05). Symptom bother had a direct effect on functional performance, as well as an indirect effect partially mediated by functional capacity (Sobel test, P = 0.004). Results suggest two possible mechanisms underlying impaired functional performance in survivors with cGVHD and underscore the importance of testing interventions to enhance functional capacity and reduce symptom bother. Bone Marrow Transplantation (2010) 45, 762-769; doi:10.1038/bmt.2009.238; published online 28 September 2009