Abstract Body (Do not enter title and authors here): Introduction: Diagnostic and prognostic value of blood cellular indices (CI) has been reported to predict the adverse outcome in various diseases including pulmonary embolism (PE). We have recently reported neutrophil to lymphocyte ratio (NLR) as the best predictive marker for short-term mortality in acute PE patients compared to platetet to lymphocyte ratio (PLR) and systemic immune inflammation index (SII). This study was designed to compare the prognostic value of NLR with other cellular indices such as neutrophil to monocyte ratio (NMR) and monocyte to lymphocyte ratio (MLR) predicting 30-day mortality outcome in patients with acute PE.

Methods: This study include 5084 patients from the RIETE Registry to evaluate the association between NLR, NMR and MLR with the 30-day mortality in PE patients. Receiver operating curve (ROC) analysis was used to define the optimal cutoff values for the ratio’s. Degree of association were analyzed by univariate chi-square and multivariate logistic regression model with all the clinically relevant variables , however, to avoid multicollinearity, ratios were modeled separately.

Result: In the cohort of 5084 patients, 49 % were male and 51% were female with the median age 71-years. Thirty-day mortality rate was 4.5%. Following ROC analysis, NLR >7.0, NMR >11.0 and MLR >0.5 were considered as the optimal cutoff for 30-day mortality. Degree of association between cellular indices and 30-day mortality were presented in table 1, elevated level of NLR, NMR, and MLR at baseline were associated with risk of death at 30-day. In both the adjusted (with clinically relevant variables) and unadjusted model, patients with elevated NLR >7.0 showed the finest association with mortality compared to NMR and MLR (figure 1).

Conclusion: Blood cellular indices is considered as a reliable and measurable prognostic marker for 30-day mortality in PE patients, however, elevated NLR at baseline supercede NMR and MLR. Further studies are obligatory to investigate the potential mechanisms by which the NLR, NMR, and MLR relates with PE outcomes to improve patient management.