The long-term effects after hematopoietic stem cell transplant on leg muscle strength, physical inactivity and fatigue

PurposeThe purpose of this study was to analyze the effects of leg muscle strength and fatigue on step-count as a measure of physical activity for people staying at home after hematopoietic stem cell transplantation (HSCT).MethodNineteen persons receiving HSCT were assessed from hospitalization until about 2 months after discharge. Mean daily step-count was taken as a measure of physical activity. Leg muscle strength was measured in three ways (knee extension, ankle plantar flexion, and ankle dorsiflexion strength) at two points in time (time of hospital discharge and after 2 months). Fatigue and anxiety were assessed using the Japanese Cancer Fatigue Scale and State-Trait Anxiety Inventory. Correlations between the above and factors affecting physical activity were also investigated by multiple regression analysis.ResultsClinical follow-up measurements in subjects were made an average of 81.0 days after discharge. Subjects with higher mean step-count during hospitalization (β = 0.647, p = 0.000) and greater ankle plantar flexion strength/kg (β = 0.361, p = 0.021) reported higher mean step-count at home (adjusted R2 = 0.701, p = 0.021). Subjects with body mass index <22.0 kg/m2 also showed higher step-counts at home compared to other subjects. Mean fatigue score at home was 16.8 (SD = 8.75), a level not associated with clinical problems, and the proportion of physical fatigue was significantly lower than during hospitalization.ConclusionMean step-count at home was most strongly affected by ankle plantar flexion strength/kg, and increasing ankle plantar flexion strength/kg was shown to promote recovery of normal physical activities.