T2 Biomarkers as Predictors of Exacerbations of Chronic Obstructive Pulmonary Disease

Type 2 (T2) biomarkers such as blood eosinophil count (BEC) and FeNO have been related to a higher risk of exacerbations in COPD. It is unknown whether combining these biomarkers could be useful in forecasting COPD exacerbations. COPD patients were enrolled in this prospective, multicenter, observational study and followed up for 1 year, during which BEC were analysed at baseline (V0) while FeNO analyses were performed at baseline (V0), 6 months (V1) and 12 months (V2). The risk of moderate or severe exacerbation during follow up was assessed by Cox regression analysis, and the predictive capacity of both measurements was assessed by ROC curves and the DeLong test. Statistical significance was assumed at P < .05. Of the 322 COPD patients initially recruited, 287 were followed up. At baseline, 28.0% were active smokers, and experienced moderate airflow limitation (mean FEV1 56.4% ± 17.0% predicted). Patients with at least one elevated T2 biomarker (n = 125, 42.5%) were at increased risk of COPD exacerbation (HR 1.75, 95% CI 1.25–2.45, P = .001) and of shorter time to first COPD exacerbation. There was no difference between BEC and FeNO regarding the predictive capacity for moderate to severe exacerbation (AUC 0.584 vs 0.576, P = .183) but FeNO predicted severe episodes more accurately than BEC (AUC 0.607 vs 0.539, P < .05). Combining the two biomarkers enhanced the detection of moderate and severe COPD exacerbations. Both eosinophil count and FeNO have limited utility for predicting COPD exacerbations. Combining these T2 biomarkers could enhance the detection of future COPD exacerbations.