Impaired respiratory and skeletal muscle strength in patients prior to hematopoietic stem-cell transplantation.

Abstract

STUDY OBJECTIVES: 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). DESIGN: Prospective observational study. SETTING: Tufts-New England Medical Center, a tertiary referral center in Boston, MA. PATIENTS: All patients (n = 56) undergoing either sibling- or unrelated-donor HSCT from January 1, 2002, to December 31, 2002. MEASUREMENTS: 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. RESULTS: 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. CONCLUSIONS: 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.