Early procalcitonin to predict mortality in critically ill COVID-19 patients: a multicentric cohort study

Background: High levels of procalcitonin (PCT) have been associated with a higher risk of mortality in COVID-19 patients. We explored the prognostic role of early PCT assessment in critically ill COVID-19 patients and whether PCT predictive performance would be influenced by immunosuppression. Methods: Retrospective multicentric analysis of prospective collected data in COVID-19 patients consecutively admitted to 36 intensive care units (ICUs) in Spain and Andorra from March to June 2020. Adult (>18 years) patients with confirmed COVID-19 and available PCT values (<72 hours from ICU admission) were included. Patients were considered as "no immunosuppression" (NI), "chronic immunosuppression" (CI) and "acute immunosuppression" (AIT if only tocilizumab; AIS if only steroids, AITS if both). The primary outcome was the ability of PCT to predict ICU mortality. Results: Of the 1079 eligible patients, 777 patients were included in the analysis. Mortality occurred in 227 (28%) patients. In the NI group 144 (19%) patients were included, 67 (9%) in the CI group, 66 (8%) in the AIT group, 262 (34%) in the AIS group and 238 (31%) in the AITS group; PCT was significantly higher in non-survivors when compared with survivors (0.64 [0.17-1.44] vs. 0.23 [0.11-0.60] ng/mL; P<0.01); however, in the multivariable analysis, PCT values was not independently associated with ICU mortality. PCT values and ICU mortality were significantly higher in patients in the NI and CI groups. Conclusions: PCT values are not independent predictors of ICU mortality in COVID-19 patients. Acute immunosuppression significantly reduced PCT values, although not influencing its predictive value.