Background: Diagnosing chronic obstructive pulmonary disease (COPD) without spirometry is still a challenge. Our objective in this study was to develop a scale for diagnosis of COPD.
Methods: Data were taken from a cross-sectional epidemiological study. After reducing chronic respiratory symptoms, a logistic regression was used to select risk factors for and symptoms of COPD. The rounded coefficients generated a Diagnosis Score for COPD (DS-COPD), which was dichotomized and differentiated between COPD and other individuals with respiratory symptoms.
Results: We constructed a tool for COPD diagnosis with good properties, comprising 12 items. The area under the curve was 0.849; the positive predictive value was 76% if the DS-COPD was >20 and the negative predictive value was 97% if the DS-COPD was <10. A DS-COPD of 10-19 represented a zone mostly suggestive of no COPD (77%). The score was also inversely correlated with forced expiratory volume in 1 second/forced vital capacity.
Conclusion: In this study, a tool for diagnosis of COPD was constructed with good properties for use in the epidemiological setting, mainly in cases of low or high scoring. It would be of particular interest in the primary care setting, where spirometry may not be available. Prospective studies and application in clinical settings would be necessary to validate this scale further.
Keywords: development; diagnosis; scale; spirometry.