Increased procalcitonin indicates antibiotic escalation in ICU patients: an observational study
Abstract Background: Empirical antibiotic therapy often fails to cover all pathogens for patients with critical infection without pathogen identification. In these patients, progressive infection can manifest as a “procalcitonin (PCT) alert”. Delayed proper antibiotic escalation could worsen their prognosis. We hypothesized that for these patients, escalating antibiotics after a “PCT alert” would improve their outcomes.Methods: This was a single-center retrospective study including patients with suspected infection who were admitted to Peking Union Medical College Hospital from January 2014 to June 2018. Patients were labelled as “antibiotic escalation” or “nonescalation” according to their antimicrobial use 48 h before and after the "PCT alert". “PCT alert” was defined as PCT ≥1.0 ng/mL that had not decreased by at least 10% from the previous day or from baseline, or a single measurement ≥ 1.0 ng/ml. Indicators that possibly influenced the prognosis were collected. 28-day intensive care unit (ICU)-free days were calculated; ICU stays >20 days and ≤20 days were considered nonprolonged ICU stays (nPISs) and prolonged ICU stays (PISs), respectively. Difference analysis and binary logistic regression were performed to determine the factors that influenced the 28-day ICU-free days . Results: A total of 1109 patients were included, 654 in the PIS group, other 455 in nPIS group. The PIS group had higher rates of pathogen identification (33.94% vs 28.13%, P=0.047) and escalated antibiotic therapy (35.47% vs 20.66%, P<0.001) but a lower proportion of surgical patients (39.45% vs 54.95%, P<0.001) than the nPIS group. Regarding PCT, the values on the 1st day (20.36±43.89 vs 14.89±30.37 ug/L, P=0.014) and on the “alert day” (24.24±46.38 vs 18.75±32.69 ug/L; P=0.021) were higher in the PIS group than nPIS group, but no significant difference in the white blood cell (WBC) count was revealed. According to the binary logistic regression model, antibiotic escalation (OR=0.552, 95% CI 0.347-0.877, P=0.012) was a negative factor for PIS, while postsurgical status (OR=1.959, 95% CI 1.269-3.023, P=0.002) and age (OR=1.020, 95% CI 1.007-1.034, P=0.003) were positive factors. Conclusions Escalating antibiotics in high-risk infection patients whose PCT does not decrease expectedly after administering broad-spectrum antimicrobials may reduce their ICU stay.