Is peak expiratory flow an accurate sarcopenia screening tool in older patients referred to respiratory rehabilitation?

Key summary points Aim To assess the performance of peak expiratory flow (PEF) for sarcopenia screening in patients with chronic obstructive pulmonary disease (COPD). Findings The PEF cut-off with highest accuracy (65.8%) was PEF ≤ 200 L/min (sensitivity 90%, specificity 62.3%, and positive and negative likelihood ratios 2.39 and 0.16, respectively). Message PEF cannot be recommended as a stand-alone screening tool for sarcopenia in older rehabilitation patients with COPD. Purpose To assess the performance of peak expiratory flow (PEF) for sarcopenia screening in patients with chronic obstructive pulmonary disease (COPD), using the revised European Working Group on Sarcopenia in Older People (EWGSOP-2) criteria as the reference standard in pulmonary rehabilitation patients; and second, to study the factors associated with low PEF in this population. Methods Diagnostic accuracy study conducted in consecutive community-dwelling COPD rehabilitation patients. Sensitivity, specificity, accuracy, likelihood ratios, predictive values, and area under the Receiver-Operating Characteristic curve were retrospectively calculated for PEF (index test) and compared with EWGSOP-2 criteria (reference standard). Results Of 151 potentially eligible patients, 79 (67.5 ± 7.1 years; 78.8% men) fulfilled inclusion criteria and 10 (12.7%) had a diagnosis of sarcopenia. The PEF cut-off with highest accuracy (65.8%) was PEF ≤ 200 L/min (sensitivity 90%, specificity 62.3%, and positive and negative likelihood ratios 2.39 and 0.16, respectively). Airway obstruction and muscle mass were significantly associated with PEF ≤ 200 L/min. Conclusions Considering the EWGSOP-2 criteria as the reference standard, a cut-off of PEF ≤ 200 L/min showed only fair validity for detecting sarcopenia, so it cannot be recommended as a stand-alone screening tool in older rehabilitation patients with COPD.