Antibiotics overuse leads to bacterial resistance. The biomarker procalcitonin rises with bacterial pneumonias and remains normal in viral respiratory tract infections. Its use can distinguish between these etiologies and thus guide antibiotics use. We aimed to quantify the effect of procalcitonin use on clinical decision-making.

A retrospective study, spanning a year at a tertiary care center, where 348 patients hospitalized with aspiration pneumonia and 824 with non-aspiration pneumonia were evaluated with regards to procalcitonin use, the length of stay (LOS) and antibiotics prescribing practices. Descriptive statistics and univariate analyses were applied to the ensemble data. Subsets of cases were manually reviewed and analyzed with descriptive statistics. P < 0.05 indicated statistical significance.

21% of both the aspiration and non-aspiration pneumonia cases had procalcitonin checked. In the ensemble analyses, a check of procalcitonin was more likely to happen in prolonged hospitalizations with aspiration pneumonia. The LOS was statistically the same regardless of procalcitonin results (elevated or normal) for both the aspiration and non-aspiration pneumonia cohorts. The overall use of antibiotics was not affected by the procalcitonin results. After excluding two extreme outliers, the per-person antibiotics cost was not affected by the procalcitonin results. Detailed chart reviews of 33 cases revealed that for the vast majority, the procalcitonin results were not used by clinicians to guide the duration of antibiotics use.

Despite its promise as a biomarker for antibiotics stewardship, procalcitonin results appeared to not be utilized by clinicians as a decision-making tool in the management of pneumonia.