Discriminative Accuracy of Simplified Spirometry for Identifying Spirometry-Defined COPD in the Community.

Abstract

The low spirometry testing rate for screening of COPD is partly attributed to complex procedures, stringent quality control requirements, and long examination times. Simplifying the spirometry protocol may increase the feasibility of COPD screening in community settings. Does the simplified spirometry protocol have high diagnostic accuracy and time efficiency in screening for COPD? We designed a community-based, cross-sectional diagnostic study. Participants completed spirometry tests using both simplified and routine protocols. Routine spirometry was defined by 3 maneuvers meeting acceptability and reproducibility criteria according to international standards; the simplified spirometry required only the first acceptable maneuver. The primary outcome was the diagnostic accuracy of prebronchodilator simplified spirometry for identifying spirometric COPD (postbronchodilator FEV₁/FVC < 0.70) measured according to the area under the receiver-operating characteristic curve. Secondary outcomes included positive predictive value, negative predictive value, sensitivity, specificity, examination time, and consistency of spirometry indicators between the 2 protocols. Of 632 screened participants, 619 were analyzed. The prebronchodilator simplified spirometry showed high diagnostic accuracy (area under the receiver-operating characteristic curve, 0.972; 95% CI, 0.955-0.983), with a positive predictive value of 77.4% (95% CI, 72.3-82.5), negative predictive value of 98.1% (95% CI, 96.6-99.5), sensitivity of 96.6% (95% CI, 94.1-99.1), and specificity of 86.0% (95% CI, 82.6-89.3) for identifying spirometric COPD. The average examination time was significantly shorter with prebronchodilator simplified spirometry compared with postbronchodilator routine spirometry (2.8 ± 2.2 minutes vs 32.1 ± 5.4 minutes; difference, 29.3 minutes [95% CI, 28.9-29.7]). A high consistency was observed between the spirometry indicators obtained from the simplified and routine protocols. Prebronchodilator simplified spirometry showed high diagnostic accuracy, sensitivity, and specificity for spirometric COPD screening in community settings. It was shown to significantly reduce examination time compared with routine spirometry, offering a feasible alternative for large-scale COPD screening initiatives.