Platelet size deviation width measured at hospital admission predicts in-hospital mortality and all cause mortality at follow up after discharge in acute pulmonary embolism

Abstract

Introduction: Platelet distribution width (PDW) directly measures the variability in platelet size and it has been postulated that large platelets may be an indi- cator of platelet activation. No data has been reported so far about the impact of this index on prognosis of acute pulmonary embolism (APE). Thus, the aim of this study was to assess the impact of PDW measured at hospital admission on both in-hospital and after discharge prognosis in patients with APE diagnosed by multislice computed tomography (MSCT). Methods and population: Retrospective, observational study that included all patients with APE diagnosed by MSCT during emergency room (ER) stay in the year of 2010. Blood tests, including PDW, were obtained at hospital admission. The primary endpoint was in-hospital death of all causes. The secondary endpoint was all-cause death at follow-up. A receiver operating characteristics (ROC) curve was used to test PDW as a predictor of the primary endpoint and to obtain the best cut-off point. Then we transformed PDW into a categorical variable with 2 groups and conducted a univariate regression analysis to test the strength of prediction. We then performed analysis for the secondary endpoint, testing the cutoff in a Cox regression model. Results: Between January and December 2010, 218 patients were diagnosed APE by MSCT (age 73±16 years, 102 males). For the outcome in-hospital mortality, area under the curve (AUC) was 0,741 (p≤ 0,001). We considered the best cut off point to be 17,55 (sensitivity 68%, specificity 78%). In the univariate regression analysis, a PDW higher than 17,55 was found to be strongly associated to worse outcome [odds ratio (OR) 7,212; 95% confidence interval (CI) 2,852–18,233; p≤0,001)]. For the outcome all cause mortality at follow up after discharge, AUC was 0,623 (p=0,01). A 17,45 cut off point was found to predict the secondary endpoint with a sensitivity of 48% and a specificity of 73%. In a Cox regression analysis, a value higher than the cut-off was associated with lower event-free survival (hazard ratio (HR) 2,52; 95% CI 1,46-4,35; p≤0,001). Conclusion: PDW is a predictor of both in-hospital mortality and all cause mortality at follow-up after APE.