PT - JOURNAL ARTICLE AU - Dinesh Shrikrishna AU - Mehul Patel AU - Rebecca J. Tanner AU - John M. Seymour AU - Bronwen A. Connolly AU - Zudin A. Puthucheary AU - Simon L.F. Walsh AU - Susannah A. Bloch AU - Paul S. Sidhu AU - Nicholas Hart AU - Paul R. Kemp AU - John Moxham AU - Michael I. Polkey AU - Nicholas S. Hopkinson TI - Quadriceps wasting and physical inactivity in patients with COPD AID - 10.1183/09031936.00170111 DP - 2012 Nov 01 TA - European Respiratory Journal PG - 1115--1122 VI - 40 IP - 5 4099 - http://erj.ersjournals.com/content/40/5/1115.short 4100 - http://erj.ersjournals.com/content/40/5/1115.full SO - Eur Respir J2012 Nov 01; 40 AB - Quadriceps weakness is an important complication of advanced chronic obstructive pulmonary disease (COPD) but few data exist concerning muscle bulk in early disease. We hypothesised that quadriceps bulk, measured by ultrasound rectus femoris cross-sectional area (USRFCSA), would be reduced in mild, as well as advanced, COPD compared with controls, and would correlate with physical activity. 161 patients with stable COPD and 40 healthy subjects had a measurement of USRFCSA and wore a multisensor armband to record physical activity. USRFCSA was reduced in Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I patients compared with healthy subjects (p=0.0002). Stage II–IV patients had reduced USRFCSA (p<0.0001) compared with controls but were not significantly different from those with stage I disease. Physical activity level was reduced in stage I (p=0.002) and stage II–IV disease compared with controls. Using regression analysis, physical activity level was independently associated with USRFCSA in stage I (p=0.01) but not stage II–IV disease, where residual volume to total lung capacity ratio was the only independent predictor of physical activity level. Quadriceps wasting exists in patients with mild, as well as advanced, COPD, and is independently associated with physical inactivity in GOLD stage I disease. The identification of these patients may guide early lifestyle and therapeutic interventions.