Impact of rehabilitation on the muscle strength and exercise tolerance in patients with interstitial pneumonia under steroid therapy

Introduction: Steroid therapy, has gained widespread acceptance as a treatment of progressive interstitial pneumonia (IP) and its acute exacerbation, leads to muscle weakness which causes ADL deterioration. We examined how rehabilitation is efficacious for countering muscle loss of patients with IP under steroid therapy, by introducing rehabilitation program to them as soon as practicable after admission. Methods: We studied 34 subjects with IP who had started steroid therapy in our hospital from January 2014 to June 2017. The subjects consisted of 24 men and 10 women with a mean of 76.8 years. 8 subjects had acute exacerbation of UIP, 22 had NSIP, 2 had CPFE and 2 had COP. Subjects were measured 6 minutes-walk distance (6MD), grip strength and lower extremity muscle strength before and after rehabilitation program. We also measured cross-sectional area of erector spinae muscles on chest CT images before rehabilitation program. Results: Results showed that rehabilitation program significantly increased 6MD of subjects from 267± 99m to 312 ± 89m. Grip strength and lower extremity muscle strength were maintained (as which were measured from 24.1±8.6kg to 26.0±7.2kg, and from 53.5±27.5kg to 55.9±26.4kg respectively). Amount of change of 6MD before and after rehabilitation program was positively correlated to the cross-sectional area of erector spinae muscles on chest. Conclusion: These observations suggest that rehabilitation program is effective for increasing 6MD of patients with IP under steroid therapy, and that increasing amount is significantly related to muscle mass.