Procalcitonin and secondary bacterial infections in COVID-19: association with disease severity and outcomes.

Vazzana, Natale; Dipaola, Francesco; Ognibene, Silvia

Introduction: Procalcitonin (PCT) is an emerging prognostic marker in coronavirus disease 2019 (COVID-19). Whether PCT can detect secondary bacterial infections or reflect target tissue injury in this setting is still unclear. Here we performed a meta-analysis to review the prognostic value of PCT for severe disease and adverse outcome events in COVID-19.Methods: We searched relevant publications in online databases. Studies were included if they reported categorical data according to disease severity and/or outcomes. We analysed extracted data using fixed or random-effects meta-analysis models, as appropriate, depending on the presence of significant heterogeneity. Results: Data from 14 studies (3492 patients) were included in the analysis. Overall, 163 of 256 patients with elevated PCT had severe disease (63.7%) compared with 553 of 2047 with negative PCT (27.0%) (OR: 5.92; 95% CI: 3.20 to 10.94). Elevated PCT was also associated with adverse outcomes (OR: 13.1; 95% CI: 7.37 to 23.1). PCT was increased in 22.8% and 30.6% of patients with the severe course and adverse outcome, respectively. Rates of secondary bacterial infections ranged from 4.7% to 19.5% and were associated with increased risk of severe course or fatal outcomes (OR: 20.8; 95% CI: 11.6 to 37.4). Conclusions: Elevated PCT levels could identify a subset of COVID-19 patients at increased risk of severe disease and adverse outcome. Its limitations include low sensitivity and undefined cost-utility ratio. Whether PCT may be used for detecting secondary bacterial infections and guiding antibiotic therapy in COVID-19 is still undefined.