ABSTRACT
Background: Studies evaluating antimicrobial stewardship programmes (ASPs) supported by computerized clinical decision support systems (CDSSs) have predominantly been conducted in single site metropolitan hospitals. Objectives: To examine outcomes of multisite ASP implementation supported by a centrally deployed CDSS. Methods: An interrupted time series study was conducted across five hospitals in New South Wales, Australia, from 2010 to 2014. Outcomes analysed were: effect of the intervention on targeted antimicrobial use, antimicrobial costs and healthcare-associated Clostridium difficile infection (HCA-CDI) rates. Infection-related length of stay (LOS) and standardized mortality ratios (SMRs) were also assessed. Results: Post-intervention, antimicrobials targeted for increased use rose from 223 to 293 defined daily doses (DDDs)/1000 occupied bed days (OBDs)/month (+32%, P < 0.01). Conversely, antimicrobials targeted for decreased use fell from 254 to 196 DDDs/1000 OBDs/month (-23%; P < 0.01). These effects diminished over time. Antimicrobial costs decreased initially (-AUD$64551/month; P < 0.01), then increased (+AUD$7273/month; P < 0.01). HCA-CDI rates decreased post-intervention (-0.2 cases/10 000 OBDs/month; P < 0.01). Proportional LOS reductions for key infections (respiratory from 4.8 to 4.3 days, P < 0.01; septicaemia 6.8 to 6.1 days, P < 0.01) were similar to background LOS reductions (2.1 to 1.9 days). Similarly, infection-related SMRs (observed/expected deaths) decreased (respiratory from 1.1 to 0.75; septicaemia 1.25 to 0.8; background rate 1.19 to 0.90. Conclusions: Implementation of a collaborative multisite ASP supported by a centrally deployed CDSS was associated with changes in targeted antimicrobial use, decreased antimicrobial costs, decreased HCA-CDI rates, and no observable increase in LOS or mortality. Ongoing targeted interventions are suggested to promote sustainability.