2170. Association Between End-of-Treatment Procalcitonin Levels with Mortality & Recurrent Ventilator-Associated Pneumonia
Authors: Schuiteman Sam , Albin Owen 
Published: December 2022

Abstract

Background
In the only randomized controlled trial utilizing procalcitonin in ventilator-associated pneumonia (VAP), 30% of patients failed to normalize procalcitonin levels by the end of treatment, a finding of uncertain clinical importance. The prognostic value of procalcitonin for VAP mortality has been examined only in studies with limited sample sizes and the relationship between end-of-treatment procalcitonin (EOT-P) and VAP recurrence—which affects up to 40% of patients with VAP—has never been examined. We aimed to determine the relationship between VAP EOT-P and recurrent pneumonia or mortality.

Methods
Retrospective single-center cohort study of hospitalized adult patients between 2013 – 2022 with VAP (defined as use of invasive mechanical ventilation for ≥ 2 days, positive respiratory culture and treatment for ≥ 5 days with pneumonia-specific antibiotics) who had serum procalcitonin levels obtained within 48 of antibiotic completion (AC). Exclusion criteria included death or discharge to hospice within 48 hours of AC. Patients with EOT-P &lt; 0.5 were compared with those with EOT-P ≥ 0.5. The primary outcome was a composite endpoint of recurrent pneumonia (defined as clinical suspicion sufficient to warrant respiratory culture collection) and/or death within 30 days of AC.

Results
Of 140 included patients, 79 (56.4%) had EOT-P levels &lt; 0.5, and 61 (43.6%) had levels ≥ 0.5. Patients with elevated EOT-P were more likely to have renal disease, longer duration of antibiotic treatment and longer antecedent hospital length of stay than those with non-elevated EOT-P. Demographic characteristics and comorbidities were otherwise similar between groups (Table 1). After multivariable adjustment, patients with elevated EOT-P were significantly more likely to have recurrent pneumonia or death within 30 days (Table 2 and Figure 1, OR 2.39 (95% 1.19-4.80 CI), adjusted OR 2.37 (95% CI 1.09-5.17)).
Patient demographics of the study group.
"EOT-P" = serum procalcitonin level drawn following completion of antibiotics. Patients with EOT-P &lt;0.5 were compared with those with EOT-P ≥ 0.5.
"Immunocompromised" = combination of HIV/AIDS positivity, actively taking immunosuppressive medications, metastatic or hematologic malignancy, history of stem cell transplant, or organ transplantation.
Patient outcomes, followed for 30 days following antibiotic completion. The primary endpoint was a composite of death or recurrent pneumonia. The secondary endpoints are death or recurrent pneumonia examined separately.
"EOT-P" = serum procalcitonin level drawn following completion of antibiotics. Patients with EOT-P &lt;0.5 were compared with those with EOT-P ≥ 0.5.
"VAP" = ventillator-assisted pneumonia.
Percentage of patients who survived without recurrence of pneumonia, followed for 30 days following antibiotic completion.
"EOT-P" = serum procalcitonin level drawn following completion of antibiotics. Patients with EOT-P &lt;0.5 were compared with those with EOT-P ≥ 0.5.

Conclusion
Elevated EOT-P in VAP was independently associated with increased VAP recurrence or mortality within 30 days. To our knowledge, this is the largest study to date of the prognostic value of procalcitonin in a ventilator-associated pneumonia cohort. Use of end-of-treatment procalcitonin in VAP may serve as a candidate biomarker to predict VAP recurrence and death.

Disclosures
Owen Albin, MD, Charles River Laboratory: Advisor/Consultant|Cipla Pharmaceuticals: Advisor/Consultant|Shionogi Inc: Advisor/Consultant.