Diagnostic score for COPD: Validation of the DS-COPD in clinical settings

Background Diagnosing Chronic Obstructive Pulmonary Disease (COPD) without spirometry is difficult; we had developed previously a scale (DS-COPD) in an epidemiological setting. It allowed diagnosing COPD confidently when scored high, and excluded confidently when low. Aim To validate the DS-COPD in clinical setting through a case-control study, and to evaluate the cost saving by its use. Methods In two tertiary care hospitals, we calculated the DS-COPD scale in suspected COPD and controls; COPD was predicted in the study sample and in symptomatic individuals. COPD status was confirmed by post-bronchodilator spirometry. Results From the ROC curve, the Area Under Curve was 0.945. The Positive Predictive Value was 79% if DS-COPD was >17 and the Negative Predictive Value was 83% if DS-COPD was <10 in symptomatic individuals. A DS-COPD of 10–17 represented a gray zone mostly suggestive of no COPD. For every 100 symptomatic patients 4150$ were saved combining spirometry and scale when inconclusive compared to systematic use of spirometry. Conclusions We were able to validate a scale (DS-COPD) for COPD diagnosis in clinical setting. It would be valuable in primary care settings, where spirometry may not be available and in clinical settings before availability of spirometry results. Future prospective studies are still needed to confirm its value.