High adherence to a procalcitonin antibiotic prescribing guideline in hospital settings is necessary to reduce antibiotic use in patients with suspected lower respiratory tract infections (LRTIs), according to a study published today in BMC Infectious Diseases.
For the study, researchers from the University of Pittsburgh conducted a retrospective analysis of data from the Procalcitonin Antibiotic Consensus Trial (ProACT), which randomized 1,656 patients with suspected LRTIs at 14 US hospitals to usual care or provision of procalcitonin assay results and an antibiotic prescribing guideline for the treating physician. ProACT found that providing clinicians with assay results for procalcitonin levels (which are typically elevated in bacterial infections and not in viral infections) and an antibiotic treating guideline did not reduce antibiotic use, as it had in several European trials.
The researchers suspected the ProACT results were because of low clinician adherence to the guidelines (64.8%) and wanted to see whether higher adherence might have made a difference. To evaluate the impact of adherence on the primary outcome of antibiotic-days by day 30, they varied adherence between 65% and 100% and determined which threshold adherence rate for low procalcitonin in the intervention arm could have allowed rejection of the null hypothesis (no difference between groups). They also determined the threshold rate for continued guideline adherence after discharge.
Analysis: 84% adherence required
The analysis found that an adherence rate of 84% in the hospital setting (emergency department and inpatient) for low procalcitonin in the intervention arm could have allowed rejection of the null hypothesis (3.7 vs 4.3 antibiotic-days). Complete guideline adherence (100%) in the hospital would have resulted in 0.9 fewer antibiotic-days. The threshold adherence rate for continued guideline adherence after discharge was 76%.
The researchers also noted that, of the 218 patients in the intervention arm who were prescribed antibiotics in the emergency department despite low procalcitonin, 153 (70.2%) were categorized as low or medium risk—a group they suggest might be more willing to forego antibiotics.
"Continued guideline adherence after discharge and withholding of antibiotics in low and medium risk patients with low procalcitonin may offer impactful potential opportunities for antibiotic reduction," they wrote.