Validation of the PESI Scale to Predict in-Hospital Mortality in Patients with Pulmonary Thromboembolism Secondary to SARS CoV − 2 Infection

OBJECTIVE: To evaluate the discriminative ability and the calibration of the Pulmonary Embolism Severity Index (PESI) to predict in-hospital mortality in patients with Pulmonary Embolism (PE) secondary to COVID 19 in two hospitals in Bogotá.

METHODS: External validation study of a prediction model based on a retrospective cohort of patients with PE secondary to COVID-19 treated at Hospital Universitario San Ignacio and Hospital universitario La Samaritana, between March 2020 and August 2021. Calibration of the scale was evaluated using the Hosmer-Lemeshow test and a calibration belt diagram. Discrimination ability was evaluated using a ROC curve.

RESULTS: 272 patients were included (median age 61.5 years, male 58.8%). PE was diagnosed in 45.6% of the patients at the time of admission. Of the remaining 54.4%, 95.9% received thromboprophylaxis until the time of diagnosis.17.6% of the patients died. Regarding calibration, the scale systematically underestimates risk in all classes of PESI. For class I, the ratio of observed/expected events was 4.4 vs 0.8%, class II 4.8 vs 1.8%, class III 15.2 vs 4.2%, class IV 14.3 vs 5.9% and class V 46.7 vs 5.8%. The calibration test rejected the adequate calibration hypothesis (p < 0.001). The discriminatory ability was adequate (AUC = 0.7128, 95% CI 0.63-0.79).

CONCLUSIONS: The PESI scale in patients with PE secondary to COVID 19 underestimates the risk of in-hospital mortality, while maintaining adequate discrimination. It is suggested not to use the PESI scale until it is recalibrated in this context.