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.
Keywords: Chronic obstructive pulmonary disease; Peak expiratory flow; Pulmonary rehabilitation; Sarcopenia; Screening.