Review of attrition and adherence in exercise studies following hematopoietic stem cell transplantation

PurposeImplementing exercise programs in people receiving high-dose chemotherapy followed by bone marrow (BMT) or hematopoietic stem cell transplantation (SCT) presents unique challenges. This review examines subject attrition rates and reasons for attrition as well as adherence to exercise interventions following BMT/SCT.MethodsStudies published between January 1985 and December 2012 that prospectively tested an exercise intervention following BMT or SCT were included in the review. Evaluation criteria included: (1) exercise modality; (2) the amount of supervision required to implement the intervention; (3) timing of the intervention; (4) subject attrition rates and reasons for attrition; and (5) exercise adherence rates.ResultsOf the 20 studies reviewed, most tested an aerobic exercise intervention or a combination of aerobic and strength training. Supervised exercise sessions were more commonly used than unsupervised sessions. The overall attrition rate was 18% for the 998 subjects enrolled in the studies. Major reasons for attrition included death, change in health status, protocol issues, personal issues with subjects, and lost to follow-up/no reason provided. Authors of supervised exercise programs rarely published exercise adherence information. Unsupervised exercise programs relied mainly on self-report to document adherence.ConclusionExercise research following BMT/SCT is becoming more sophisticated as researchers build upon the expanding literature base. Questions regarding subject attrition and adherence to exercise interventions must be addressed to identify interventions that are likely to be successful when translated into clinical practice. Subject attrition from exercise studies following BMT/SCT is relatively low. Adherence information for exercise interventions needs to be regularly addressed.