Impaired Respiratory and Skeletal Muscle Strength in Patients Prior to Hematopoietic Stem-Cell Transplantation

Abstract

The primary aim was to determine if respiratory and skeletal muscle strength and submaximal exercise capacity were reduced in subjects prior to sibling- or unrelated-donor hematopoietic stem-cell transplantation (HSCT). Prospective observational study. Tufts-New England Medical Center, a tertiary referral center in Boston, MA. All patients (n = 56) undergoing either sibling- or unrelated-donor HSCT from January 1, 2002, to December 31, 2002. Demographic data, chemotherapy burden, pulmonary function tests (PFTs), maximal inspiratory muscle strength (PImax), maximal expiratory muscle strength (PEmax), dominant hand grip strength (GS), 6-min walk test (6MWT), and survival as of May 21, 2004. PImax was reduced to < 80% predicted in 42% of subjects and to < 60% predicted in 18% of subjects. PEmax was reduced to < 80% predicted in 89% of subjects and to < 60% of predicted in 80% of subjects. A significant correlation was observed between PImax and PEmax (r = 0.65, p < 0.0001). GS was reduced to < 80% predicted in 39% of subjects and < 60% predicted in 15% of subjects. The 6MWT was reduced to < 80% predicted in 58% of subjects and to < 60% predicted in 9.6% of subjects. Diffusing capacity of the lung for carbon monoxide (Dlco) was the only PFT that was significantly correlated with 6MWT distance (r = 0.44, p = 0.015). The mean calculated load of chemotherapy was 14.8 +/- 16.5 U (+/- SD). The mean time elapsed from date of hematologic diagnosis to date of HSCT was 874 +/- 1,109 days. The median survival of the cohort was 374 days (95% confidence interval, 177 to 665 days). Respiratory or skeletal muscle strength, 6MWT distance, or calculated burden of chemotherapy did not predict survival. Respiratory and skeletal muscle strength and submaximal exercise capacity are reduced in a significant percentage of patients prior to undergoing HSCT. These observations may help explain musculoskeletal weakness that has been reported in the posttransplant period.