Immature platelet fraction as a systemic inflammation marker in patients with chronic obstructive pulmonary disease

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.