Immature Platelet Fraction as a Surrogate Marker of Thrombo-Inflammation in Hospitalized COVID-19 Patients.

Although COVID-19 is associated with significant thrombo-inflammatory complications, reliable biomarkers to guide antithrombotic therapy remain limited. Immature platelet fraction (IPF) reflects platelet turnover and may indicate heightened thrombotic risk. We retrospectively analyzed 133 hospitalized COVID-19 patients (median age 68 years) at a single center. IPF and inflammatory markers (WBC, ANC, D-dimer, LDH, CRP) were measured on admission. Correlations between IPF and these biomarkers were assessed overall and in clinical subgroups (age, sex, disease severity, comorbidities, and treatment). We found that IPF was positively correlated with WBC and ANC in patients less than 70 years old (r = 0.36 and 0.33, respectively; p < 0.05), males, and those with moderate-to-severe disease. Among patients with congestive heart failure, IPF correlated strongly with D-dimer (r = 0.78, p = 0.013). Similar associations were observed in patients requiring enoxaparin or antiplatelet therapy. No significant correlations were found in patients age 70 or older. Based on these findings, we conclude that elevated IPF is associated with increased inflammatory and thrombotic activity in hospitalized COVID-19 patients, especially in younger, male, and more severe cases. These findings suggest IPF may serve as a dynamic marker for thrombo-inflammation and help identify patients who might benefit from more intensive antithrombotic therapy. Larger studies are warranted to validate IPF as a biomarker for personalized management of COVID-19.