Moderator Effects in a Randomized Controlled Trial of Exercise Training in Lymphoma Patients

Abstract

Background: The Healthy Exercise for Lymphoma Patients trial showed that aerobic exercise training improved important health outcomes in lymphoma patients. Here, we examine potential moderators of the exercise training response. Methods: Lymphoma patients were stratified by major disease type and current treatment status and randomly assigned to usual care (n = 62) or aerobic exercise training (n = 60) for 12 weeks. Endpoints were quality of life, cardiovascular fitness, and body composition. Moderators were patient preference for group assignment, age, sex, marital status, disease stage, body mass index, and general health. Results: Patient preference did not statistically moderate the effects of exercise training on quality of life (P for interaction = 0.36), but the interaction effect of 7.8 points favoring patients with no preference was clinically meaningful. Marital status (P for interaction = 0.083), general health (P for interaction = 0.012), and body mass index (P for interaction = 0.010) moderated the effects of aerobic exercise training on quality of life with better outcomes for unmarried versus married patients, patients in poor/fair health versus good-to-excellent health, and normal weight/obese versus overweight patients. Disease stage (P for interaction = 0.056) and general health (P for interaction = 0.012) moderated the effects of aerobic exercise training on body composition with better outcomes for patients with advanced disease versus early disease/no disease and patients in good health versus very good-to-excellent health. No variables moderated intervention effects on cardiovascular fitness. Findings were not explained by differences in adherence. Conclusions: Clinically available variables predicted quality of life and body composition responses to aerobic exercise training in lymphoma patients. If replicated, these results may inform future randomized trials and clinical practice. (Cancer Epidemiol Biomarkers Prev 2009;18(10):2600–7)