Validation and Clinical Analysis of the Quantitative COPD Exacerbation Recognition Tool (Q-CERT): Diagnostic Performance and Association with Lung Function Impairment

Xingru Zhao,1,* Chao Zhou,1,* Yongqin Liu,1,* Kai Cui,1 Paul Jones,2 Yunxia An,1 Xiaoju Zhang1 1Department of Respiratory and Critical Care Medicine, Zhengzhou University People’s Hospital, Henan Provincial People’s Hospital, Zhengzhou, People’s Republic of China; 2Department of Respiratory Medicine, St. George’s University of London, London, UK*These authors contributed equally to this workCorrespondence: Yunxia An, Department of Respiratory and Critical Care Medicine, Zhengzhou University People’s Hospital, Henan Provincial People’s Hospital, Zhengzhou, 450003, People’s Republic of China, Email [email protected] Xiaoju Zhang, Department of Respiratory and Critical Care Medicine, Zhengzhou University People’s Hospital, Henan Provincial People’s Hospital, Zhengzhou, 450003, People’s Republic of China, Email [email protected]: There is a need for a patient-centered tool that can quantitatively identify acute exacerbations of COPD. This study aims to develop and validate a digital tool that enables such care by providing a quantifiable severity score.Methods: A total of 161 AECOPD patients and 130 stable COPD patients from Henan Provincial People’s Hospital were enrolled. Demographics, clinical symptoms, pulmonary function parameters and admission laboratory data for patients were collected. The COPD Exacerbation Recognition Tool (CERT) was quantified using a 4-point Likert scale (0– 3) to derive the Quantitative-CERT (Q-CERT) score. Effectiveness of the CERT and Q-CERT in identifying AECOPD was assessed.Results: The CERT demonstrated strong diagnostic performance for recognizing AECOPD, with a sensitivity of 85.7%, specificity of 80.8%, and accuracy of 83.5%. The quantitative Q-CERT score further optimized diagnostic accuracy. At a cutoff of 5 points, the Q-CERT provided optimal sensitivity (89.4%) and specificity (83.8%) combination, with an AUC of 0.956 (95% CI: 0.937– 0.976, P< 0.001). Q-CERT scores were significantly higher in patients with AECOPD than in those with stable COPD (8 vs. 0 points, P< 0.001). Furthermore, elevated Q-CERT scores correlated negatively with pulmonary function parameters, including FEV1%pred, FEV1/FVC, MEF75%pred, MEF50%pred, and MMEF%pred (r = − 0.406 to − 0.358, all P < 0.001), with the strongest associations observed in small airway metrics. Conversely, higher Q-CERT scores showed positive correlations with the neutrophil-to-lymphocyte ratio (NLR) (r = 0.181, P< 0.05) and platelet-to-lymphocyte ratio (PLR) (r = 0.245, P< 0.05).Conclusion: Q-CERT enhanced the original CERT’s ability to identify AECOPD. And total score was correlated with pulmonary function impairment and systemic inflammation, making it an efficient and reliable tool for clinical practice.Keywords: chronic obstructive pulmonary disease, COPD, acute exacerbation, COPD exacerbation recognition tool, CERT, patient-centered monitoring