Sarcopenia in Japanese patients with COPD: prevalence, relationship with COPD severity

Background: Sarcopenia is defined as the loss of skeletal muscle mass and muscle strength that occurs with advancing age. It is also recognized as one of the complications of COPD. Japan is now aging more rapidly than anywhere else in the world. Purpose: To evaluate the prevalence of sarcopenia in Japanese COPD patients and determine whether sarcopenia correlates with the severity of COPD Methods: 61 out-patients (57 males / 4 females, mean age 73.7 ± 7.3) who received treatment with COPD were studied. After a 6-minute walk test (6 MWT) and grip strength measurement, body composition was measured through the bioelectrical impedance analysis (BIA) method to calculate SMI. The diagnosis of Sarcopenia was conducted by the diagnostic criteria of the Asian Working Group for Sarcopenia. We also attempted to determine whether SMI correlates with FEV1.0, modified British Medical Research Council questionnaire (mMRC), COPD Assessment Test (CAT), serum albumin and prealbumin. Results: Sarcopenia was confirmed in 19 of 61 (31.1%) patients. SMI showed a correlation with BMI (r = 0.83, P < 0.01), however sarcopenia was also observed 27.8% in 18.5 < BMI < 25 group and 18.2% in BMI ≥ 25 group. As the degree of obstruction (FEV1) progressed, the sarcopenia was increased. However SMI was not associated with FEV1 or with mMRC or with CAT. There was a correlation between SMI and prealbumin (r = 0.542, p < 0.01), but SMI was not correlated with albumin (r = 0.149, p = 0.487). Conclusions: Sarcopenia was observed in 31.1% of Japanese COPD patients. It was increased as the degree of obstruction progressed. As sarcopenia was also observed 18.5% in the BMI> 25 group, early diagnosis by the BIA method is effective.