RESUMO
INTRODUCTION: Recently, there has been an increasing interest to find a simple, low cost, widely available biomarker for outcome predictors in chronic obstructive pulmonary disease (COPD). METHODS: Absolute immature platelet count (AIPC), the percentage of AIPC to the total platelet count (immature platelet fraction [IPF%]), symptoms, spirometry results, age-dyspne-airflow obstruction index, and C-reactive protein tests of COPD patients and control group were recorded. Neutrophil/lymphocyte, monocyte/lymphocyte, and platelet/lymphocyte ratios and Charlson comorbidity index scores were calculated. RESULTS: One hundred and thirty-four COPD patients and 30 healthy control subjects were included in the study. Eighty-nine patients were in exacerbation (AECOPD) and 45 of them were in stable COPD period. There was a difference between IPF% values and AIPC of COPD group and control group (3.45 ± 2.41 vs. 2.04 ± 1.12, p = 0.01; 5.87 ± 2.45 vs. 5.20 ± 3.02, p = 0.01). A positive correlation was observed between IPF% with white blood cell count and neutrophil/lymphocyte ratio, platelet/lymphocyte ratio, monocyte/lymphocyte ratio in all patients (r = 0.352, p < 0.001; r = 0.399, p < 0.001; r = 0.186, p = 0.032; r = 0.200, p = 0.021) and AECOPD (r = 0.356, p < 0.001; r = 0.414, p < 0.001; r = 0.239, p = 0.025; r = 0.273, p = 0.010). At a cut-off of 3.4, IPF% showed the highest accuracy in identifying COPD (sensitivity: 80.3%, specificity: 82.5%) using receiver-operating characteristic analysis. CONCLUSION: This is the first study to examine the relationship between AIPC, IPF%, and COPD. The higher IPF% values in COPD and the positive correlation between IPF% and other inflammatory markers are suggested that IPF may be an indicator of systemic inflammation in COPD.