Association of Antibiotics with the Outcomes in Covid-19 Patients with Elevated Pct Levels

Objective: To assess antibiotic impact on outcomes in COVID-19 pneumonia patients with varying procalcitonin (PCT) levels. Methods: This retrospective cohort study included 3,665 COVID-19 pneumonia patients hospitalized at five Mayo Clinic sites (March 2020 to June 2022). PCT levels were measured at admission. Patients’ antibiotic use and outcomes were collected via the Society of Critical Care Medicine (SCCM) Viral Infection and Respiratory Illness Universal Study (VIRUS) registry. Patients were stratified into high and low PCT groups based on the first available PCT result. The distinction between high and low PCT was demarcated at both 0.25 ng/ ml and 0.50 ng/ml.  Results Our cohort was predominantly male, Caucasian and non-Hispanic. With the PCT cut-off of 0.25 ng/ml, 1,290 (35.2%) had PCT ≥ 0.25 ng/ml and 731(19.94%) patients had a PCT ≥ 0.50 ng/ml, when the PCT cut off of 0.50 ng/ml was used. Patients with higher PCT levels exhibited significantly higher rates of bacterial infections (0.25 ng/ml cut-off: 4.2% vs 7.9%; 0.50 ng/ml cut-off: 4.6% vs 9.2%). Antibiotic were used in 66.0% of the cohort. Regardless of the PCT cutoffs, the antibiotic group showed increased hospital length of stay (LOS), intensive care unit (ICU) admission rate, and mortality. However, early de-escalation (<24 hr) of antibiotics correlated with reduced hospital LOS, ICU LOS, and mortality. These results were consistent even after adjusting for confounders. Conclusion: Our study shows that antibiotic use in COVID pneumonia patients with   PCT < 0.5 in the absence of clinical evidence of bacterial infection has no beneficial effect.