Using Pneumonia Severity Index and CURB-65 to Predict COVID-19 Pneumonia Deaths

COVID-19 pneumonia chest X-ray
Are CURB-65 and PSI effective predictors of inpatient COVID-19 mortality, and would added measures for d-dimer and procalcitonin improve their predictive value?

The pneumonia severity index (PSI) and CURB-65 (confusion, uremia, respiratory rate, BP, age 65 years and older) criteria, established predictors of mortality in patients hospitalized with community-acquired pneumonia (CAP), may have even greater value for predicting mortality in patients with SARS-CoV-2 CAP, according to research recently published in CHEST. Notably, researchers also found that adding criteria related to D-dimer or procalcitonin to these scoring tools did not improve their predictive value, regardless of the etiology of CAP.

Although PSI and CURB-65 have been used to predict CAP, their use with regard to COVID-related CAP has not been widely investigated. According to the authors, quick and accurate analysis of mortality risk permits clinicians to triage/optimize management of high-risk patients, thus the importance of optimized models.

In the current secondary, population-based analysis, investigators assessed the predictive value of PSI and CURB-65 as prognostic tools for CAP mortality using 2 prospective cohorts of adult patients — a SARS-CoV-2 CAP cohort and a non-SARS-CoV-2 CAP cohort — from 8 hospitals in Louisville, KY. The study involved a total of 8081 patients, including 632 (8%) with SARS-CoV-2 CAP. The SARS-CoV-2 CAP cohort had a median age of 63 and included 47% males, 31% Black individuals, 12% Hispanic individuals. The in-hospital mortality rate was 19% for patients with SARS-CoV-2 CAP and 6.5% for patients with non-SARS-CoV-2 CAP. Notably, in the SARS-CoV-2 CAP cohort, those who died were older and had more comorbidities.

Compared to patients with non-SARS-CoV-2 CAP, patients presenting with SARS-CoV-2 CAP had a higher mortality rate in every PSI risk class and every CURB-65 score. The AUC for PSI was 0.82 (95% bCI [bootstrap standard CI], 0.78-0.86) in patients with SARS-CoV-2 CAP and 0.79 (95% bCI, 0.77-0.80) in patients with non-SARS-CoV-2 CAP. The AUC for CURB-65 was 0.79 (95% bCI, 0.75-0.84) in patients with SARS-CoV-2 CAP and 0.75 (95% bCI, 0.73-0.77) in patients with non-SARS-CoV-2 CAP. Notably, the addition of D-dimer and procalcitonin criteria did not substantially improve the predictive ability of PSI or CURB-65, despite the biological rationale for adding these measures.

Investigators noted that a remarkable difference in the positive predictive value of the 2 tools between patients with SARS-CoV-2 CAP vs non-SARS-CoV-2 CAP was found, which was likely attributable to the increased prevalence of poor outcomes in patients with SARS-CoV-2 CAP. Researchers thus concluded that the high negative-predictive value of the 2 scoring tools for CAP regardless of etiology (> 94%) suggested that the scoring systems were best suited for picking out patients at low-risk for death.

A limitations of the current study was that participants were recruited from only 1 city, potentially inhibiting extrapolation of study findings to other populations. Other limitations are that D-dimer and procalcitonin were not analyzed in all patients, and the treatment of COVID is continuously changing.


Bradley J, Sbaih N, Chandler TR, et al. Pneumonia severity index and curb-65 are good predictors of mortality in hospitalized patients with SARS-COV-2 community-acquired pneumonia. Chest. Published online November 2, 2021. doi:10.1016/j.chest.2021.10.031