The relation between international normalized ratio and mortality in acute pulmonary embolism: A retrospective study.

Background: Acute pulmonary embolism (PE) is a serious clinical disease characterized by a high mortality rate. The aim of this study was to assess the prognostic value of international normalized ratio (INR) in acute PE patients not on anticoagulant therapy.

Methods: The study included 244 hospitalized acute PE patients who were not receiving previous anticoagulant therapy. Based on their 30-day mortality, patients were categorized as survivors or non-survivors. INR was measured during the patients' admission, on the same day as the diagnosis of PE but before anticoagulation started.

Results: Thirty-day mortality occurred in 39 patients (16%). INR was higher in non-survivors than in survivors (1.3±0.4 vs 1.1±0.3, P=.003). In multivariate analysis, INR (HR: 3.303, 95% CI: 1.210-9.016, P=.020) was independently associated with 30-day mortality from PE. Inclusion of INR in a model with simplified pulmonary embolism severity index (sPESI) score improved the area under the receiver operating characteristics (ROC) curve from 0.736 (95% CI: 0.659-0.814) to 0.775 (95% CI: 0.701-0.849) (P=.028). Also, the addition of INR to sPESI score enhanced the net reclassification improvement (NRI=8.8%, P<.001) and integrated discrimination improvement (IDI=0.043, P=.027).

Conclusion: Elevated INR may have prognostic value for 30-day mortality in acute PE patients not on anticoagulation. Combining INR with sPESI score improved the predictive value for all-cause mortality. However, further large-scale studies are needed to confirm it's prognostic role.