Effect of a clinical procalcitonin algorithm to guide antibiotic therapy in patients with lower respiratory tract infections outside study conditions: a post-study survey

Introduction

A procalcitonin (PCT) algorithm was demonstrated to reduce antibiotic exposure in patients with lower respiratory tract infections (LRTI) in several randomised controlled trials. Data on the efficacy of PCT-guided antibiotic stewardship in real life and outside study conditions are lacking.

Methods

We prospectively monitored antibiotic therapy and adherence to the published PCT algorithm in consecutive hospitalized patients with LRTI admitted to the Kantonsspital Aarau (Switzerland), a former ProHOSP study hospital [1], between April and November 2008.

Results

Median age of the 130 included patients (36% females) was 70 (IQR 57 to 82) years. Community-acquired pneumonia was diagnosed in 78%, while 17% had acute and 5% had exacerbation of chronic bronchitis. Mortality rate was 11.5% and 6.9% of patients needed ICU admission. In 70% of patients (n = 91), antibiotics were administered or withheld according to the PCT algorithm. In the 39 patients (30%) where the PCT algorithm was overruled, the main reasons were severe immunosuppression (30%), high-risk LRTI (13%), other infections (8%) and clinical judgement of the treating physician (33%). Overall, the median duration of antibiotic therapy was 6 days (IQR 1 to 10), 4 days (IQR 0 to 7) when the PCT algorithm was followed and 10 days (IQR 8 to 14) when it was overruled, respectively. In patients with community-acquired pneumonia, median days on antibiotic therapy was 7 days (IQR 4 to 10), which was similar to the PCT group in a trial in the same institution (P = 0.44) [1].

Conclusion

The present study mirrors the use of PCT-guided antibiotic therapy in clinical practice and outside trial conditions. Antibiotic exposure, however, strongly depends on the adherence to a clinical PCT algorithm.