Characterization Associated with the Frequent Severe Exacerbator Phenotype in COPD Patients

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease with exacerbations causing hospitalizations, morbidity, and mortality. COPD exacerbation causes a substantial health impact, and its subtypes might differ in prognosis and treatment response. METHODS: This study evaluated the factors of COPD exacerbations and explored the probabilities of frequent severe COPD exacerbations. Categorical and continuous variables between groups were compared. The hazard ratio (HR) and the probability of no hospital readmission were also estimated. RESULTS: A total of 617 COPD patients were enrolled and comprised the frequent exacerbator (N = 226) and the non-frequent exacerbator (N = 391) groups. The frequent exacerbator group significantly displayed a higher eosinophil count (EC; p=0.004), a higher percentage of the frequent severe acute exacerbation history before the index hospitalization (IH; p < 0.001), a lower FEV1 value (p=0.001), and a higher triple combination inhaler prior and following the IH (p < 0.001 and p=0.002) than the non-frequent exacerbator one. Increasing age (aOR of 1.02), higher EC (aOR of 1.09), and lower FEV1 value (aOR of 0.72) were significantly associated with an increased hospital readmission risk. The readmission rate and risk were higher in patients with a history of frequent severe acute exacerbation (aHR of 3.38) than those without severe acute exacerbation. Cases treated with the triple combination inhaler before the IH had a higher readmission rate and risk than non-users. CONCLUSION: Patients with EC ≥2%, FEV1 <50%, or frequent severe acute exacerbation history before the IH have a higher risk of being diagnosed with a frequent exacerbator phenotype. Besides, higher age, triple combination inhaler before the IH, and smoking might be independently correlated with the frequent readmission risk within 1-year post-exacerbation. A better comprehension of the COPD exacerbation mechanism may further identify the best course of preventative strategy and lead to novel interventions.