Impact of requiring re-authorization of restricted antibiotics on day 3 of therapy

Background: Pre-authorization of restricted antibiotics is a core component of an antibiotic stewardship programme (ASP). On day 3, information about culture results and clinical status is typically available. Our objective was to compare an ASP that requires initial authorization alone with one requiring initial authorization and re-authorization on day 3 of therapy. Methods: A single-centre, retrospective, before and after study was conducted. Randomly selected adults were eligible if receiving a restricted antibiotic for ≥3 days during April to June in 2012 (pre-intervention) and during the same months in 2013 (post-intervention). The target sample size was 166 patients. The intervention required re-authorization of restricted antibiotics that were continuing on day 3. The days of therapy of restricted antibiotic(s), length of hospital stay (LOS) and hospital mortality were compared between pre- and post-intervention periods. Results: The ASP intervention was associated with a decrease in median days of therapy from 5 (4-9) to 4 (3-5) days (P < 0.001) for all restricted agents, from 5 (3-6) to 3 (3-5) days for broad-spectrum Gram-negative agents (P < 0.001) and from 6.5 (6-7) to 3 (3-4.5) days for oral vancomycin. The proportion of subjects receiving restricted agents for >4 days decreased from 57.8% to 30.1% (P < 0.001). LOS decreased from 8 (5-17) to 6 (5-9) days (P = 0.005) without a significant change in hospital mortality. Conclusions: Requiring re-authorization of restricted antibiotics on day 3 of therapy in addition to initial authorization was associated with reduction in overall consumption of restricted antibiotics and LOS without adversely affecting hospital mortality.