PROMIS is funded by the UK Government Department of Health, National Institute of Health Research-Health Technology Assessment Programme, (Project number 09/22/67). This project is also supported and partly funded by UCLH/UCL Biomedical Research Centre and The Royal Marsden and Institute for Cancer Research Biomedical Research Centre and is coordinated by the Medical Research Council Clinical Trials Unit (MRC CTU) at UCL. It is sponsored by University College London (UCL).

Background: Quadriceps weakness and loss of muscle mass predict mortality in chronic obstructive pulmonary disease (COPD). It was hypothesised that a reduced quadriceps cross-sectional area could be detected by ultrasound in patients with COPD compared with healthy subjects, and that measurements relate to strength and fat-free mass (FFM). Methods: Rectus femoris muscle cross-sectional area (RF CSA ) was measured by ultrasound and whole-body FFM estimated using electrical bioimpedance. Quadriceps strength was measured by maximum voluntary contraction and twitch tension (TwQ) following magnetic femoral nerve stimulation. Results: 26 healthy volunteers of mean (SD) age 63 (9) years and 30 patients with COPD of mean (SD) age 67 (9) years and percentage predicted forced expiratory volume in 1 s (FEV 1 ) 48.0 (20.8)% with a similar FFM (46.9 (9.3) kg vs 46.1 (7.3) kg, p = 0.193) participated in the study. Mean RF CSA was reduced in patients with COPD by 25% of the mean value in healthy subjects(2115 mm 2 ; 95% CI 2177 to 254, p = 0.001) and was related to MRC dyspnoea scale score, independent of FFM or sex. Maximum voluntary contraction strength was linearly related to RF CSA in patients with COPD (r = 0.78, p,0.001). TwQ force per unit of RF CSA was similar in both healthy individuals and those with COPD (mean (SD) 17 (4) g/mm 2 vs 18 (3) g/mm 2 , p = 0.657). Voluntary contraction strength per unit of RF CSA was dependent on central quadriceps activation and peripheral oxygen saturation in COPD. Conclusion: Ultrasound measurement of RF CSA is an effort-independent and radiation-free method of measuring quadriceps muscle cross-sectional area in patients with COPD that relates to strength.Even in non-cachectic patients with chronic obstructive pulmonary disease (COPD), quadriceps strength is typically reduced by up to 30% compared with healthy elderly subjects. 1 Quadriceps strength has been shown independently to predict increased healthcare utilisation and mortality in COPD. 2 3 In our cohort of patients with moderate to severe COPD, quadriceps strength together with age provided more powerful prognostic information than whole body fat-free mass (FFM) or forced expiratory volume in 1 s (FEV 1 ). 3 A related measure, mid-thigh cross-sectional area measured by computed tomography (CT), has also been shown to predict mortality. 4 Quadriceps strength may be assessed by maximum voluntary contraction force, but maximum effort cannot be guaranteed and formal testing equipment is cumbersome. 5 6 Effort-independent methods of assessing strength such as femoral nerve stimulation are expensive, not widely available and require specific expertise. 7 Bedside tests are attractive for their simplicity and accessibility but measurement of thigh circumference, for example, may not accurately reflect the muscle compartment. Ionising radiation exposure makes serial measurements with CT 4 or dual energy x ray absorptiometry scanning 8 9 undesirable in large populations. MRI avoids this concern, but accessibility and long scann...

Background Exacerbations of chronic obstructive pulmonary disease (COPD) are characterised by increased dyspnoea, reduced quality of life and muscle weakness. Re-exacerbation and hospital admission are common. Pulmonary rehabilitation (PR) administered after hospital admission for an exacerbation can improve quality of life and exercise capacity. Objective To determine whether outpatient postexacerbation PR (PEPR) could reduce subsequent hospital admission episodes. Methods Patients admitted to hospital for an exacerbation of COPD were randomised to receive either usual follow-up care (UC) or PEPR after discharge. Hospital admission and emergency department attendances for COPD exacerbations were recorded over a 3-month period and analysed on an intention-to-treat basis. Secondary outcomes included exercise capacity and quadriceps strength. Results 60 patients underwent concealed randomisation at the time of their hospital discharge (UC: n¼30, mean (SD) age 65 (10) years, forced expiratory volume in 1 s (FEV 1 ) 52 (22)% predicted; PEPR: n¼30, 67(10) years, 52 (20)% predicted). The proportion of patients readmitted to hospital with an exacerbation was 33% in the UC group compared with 7% in those receiving PEPR (OR 0.15, 95% CI 0.03 to 0.72, p¼0.02). The proportion of patients that experienced an exacerbation resulting in an unplanned hospital attendance (either admission or review and discharge from the emergency department) was 57% in the UC group and 27% in those receiving PEPR (OR 0.28, 95% CI 0.10 to 0.82, p¼0.02). Conclusions Post-exacerbation rehabilitation in COPD can reduce re-exacerbation events that require admission or hospital attendance over a 3-month period. Clinical Trials Registration Number NCT00557115.