Usefulness of C-reactive protein to determine the severity of SARS-CoV-2 infection in Peru

Abstract

Background: Recently, many biomarkers have been studied to determine severe cases of COVID-19. C-reactive protein (CRP) has shown high sensitivity in identifying patients with severe disease and utility comparable to computed tomography. Aim: To determine the usefulness of CRP to predict the severity of SARS-CoV-2 infection in patients hospitalized at the Naval Medical Center of Peru during the period January-September in the year 2021. Methods: A quantitative, observational, analytical, retrospective, and diagnostic test type design was used. A sample size of 503 patients was calculated, which were divided into two groups according to their severity. Results: An optimal cut-off point of 10.92 mg/L for CRP levels was determined for the diagnosis of severe COVID-19. An area under the curve (AUC) of 0.762 was calculated and sensitivity, specificity, positive and negative predictive values and diagnostic accuracy values of 78.88%, 66.4%; 41.42%; 87.01%; and 67.27%; respectively. Fagan's normogram showed a post-test probability of 41%. In the adjusted model, CRP (aOR = 4.853; 95% CI 2.987-7.886; p = 0.001), ferritin (aOR = 1.001; 95% CI: 1.001 - 1.002; p = 0.001) and hypothyroidism (adjusted OR = 4899; 95% CI: 1272 – 18872; p = 0.021) showed significance. Conclusions: The present study showed an association between CRP and the severity of SARS-CoV-2 infection in an adjusted model, showing its potential utility and contributing to determine the cut-off point of CRP in the Peruvian population and its international comparison.