Sustained impact of a computer-assisted antimicrobial stewardship intervention on antimicrobial use and length of stay

Objectives: Prospective audit and feedback interventions are the core components of an antimicrobial stewardship programme. Herein, we describe the sustained impact of an antimicrobial stewardship programme, based on a novel clinical decision-support system (Antimicrobial Prescription Surveillance System; APSS), on antimicrobial use and costs, hospital length of stay (LOS) in days and the proportion of inappropriate antimicrobial prescriptions. Methods: A quasi-experimental, retrospective study was conducted using interrupted time series between 2008 and 2013. Data on all hospitalized adults receiving antimicrobials were extracted from the data warehouse of a 677 bed academic centre. The intervention started in August 2010. Prospective audit and feedback interventions, led by a pharmacist, were triggered by APSS based on deviations from published and local guidelines. Changes in outcomes before and after the intervention were compared using segmented regression analysis. Results: APSS reviewed 40 605 hospitalizations for 35 778 patients who received antimicrobials. The intervention was associated with a decrease in the average LOS (level change -0.92, P < 0.01; trend -0.08, P < 0.01; intercept 11.4 days), antimicrobial consumption in DDDs/ 1000 inpatient days (level change -32.4, P < 0.01; trend -1.12, P < 0.02; intercept 243 DDDs per 1000 days of hospitalization), antimicrobial spending in Canadian dollars (level change -19 649, P = 0.01; trend -1881, P < 0.01; intercept $74 683) and proportion of non-concordance with local guidelines for prescribing antimicrobials (level change -2.3, P =0.04; intercept 41%). Conclusions: The implementation of the APSS-initiated strategy was associated with a positive impact on antimicrobial use and spending, LOS and inappropriate prescriptions. The high rate of accepted interventions may have contributed to these results.