Procalcitonin guidance for reduction of antibiotic use in low‐risk outpatients with community‐acquired pneumonia

BACKGROUND AND OBJECTIVE: Use of antibiotics in outpatients with community-acquired pneumonia (CAP) is empirical, which may lead to overuse and selection pressure for resistance. Procalcitonin (PCT) levels may predict the severity of CAP and may be used to guide antibiotic use in hospitalized patients. This study evaluated the value of PCT measurements for guiding antibiotic use in low-risk outpatients with CAP. METHODS: This was a randomized intervention trial conducted between February 2005 and December 2008 that included 172 consecutive patients with suspected CAP, of whom 156 completed the study. The control group received antibiotics according to current guidelines. In the PCT group, antibiotic treatment was based on PCT levels as follows: 0.25 µg/L, encouraged. The primary end-points were total antibiotic use and duration of antibiotic treatment; laboratory and clinical outcomes were measured. RESULTS: Prescription of antibiotics on admission (84.4% vs 97.5%; P = 0.004), total antibiotic exposure (relative risk 0.55, 95% CI: 0.51-0.60; P = 0.003) and duration of antibiotic treatment (median 5 days vs 7 days; P < 0.001) were reduced in the PCT guidance group, compared with patients treated according to current guidelines. At 4-week follow up, all patients had survived and laboratory and clinical outcomes were similar in the two groups. CONCLUSIONS: Under PCT guidance, antibiotic use was reduced and duration of antibiotic treatment was shortened in low-risk outpatients with CAP, without apparent harm.