Objectives: The choice of treatment according to the inflammation type in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) has been of recent interest. This study investigated the role of novel biomarkers, hospital outcomes, and readmission rates in the first month in patients with eosinophilic or neutrophilic AECOPD.
Materials and methods: We conducted a retrospective observational cohort study in a Chest Teaching Hospital with hospitalized AECOPD patients. Subjects' characteristics, hemogram results, C-reactive protein (CRP), neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), platelet/mean platelet volume (PLT/MPV), length of hospital stay, mortality, and steroid use were recorded. Eosinophilic AECOPD defined as peripheral blood eosinophilia (PBE) was >2% and neutrophilic AECOPD as PBE ≤2%. Readmission within 28 days of discharge was recorded.
Results: Of 2727(31.5% females) patients, eosinophilic AECOPD was found in 510 (18.7%) patients. Leucocytes, CRP, NLR, and PLR were significantly higher in neutrophilic AECOPD than in eosinophilic AECOPD (p<0.001). Steroid use and mortality rate were 45% and 0.6% in eosinophilic AECOPD and 71%, and 1.4% in neutrophilic AECOPD, respectively (p=0.001, p=0.19). Age >75 years, albumin <2.5 g/dL, CRP >50 mg/dL, and PLT/MPV <20×103 were found to be risks factors for hospital mortality (p<0.05 each). Readmission rates within 28 days of discharge were 5% (n=136), and this rate was higher in eosinophilic AECOPD patients not taking steroids (p<0.001).
Conclusion: NLR, PLR, and CRP levels were higher in neutrophilic AECOPD compared with eosinophilic AECOPD. These markers decreased with treatment in neutrophilic AECOPD. A PLT/MPV ratio of <20×103 resulted in an increased mortality rate. Thus, appropriate steroid therapy may reduce readmission rates in the first 28 days after discharge in eosinophilic AECOPD.