LAUSR

Abstract Objective We implemented a stepwise antimicrobial stewardship program (ASP). This study evaluated the effect of each intervention and the overall economic impact on carbapenem (CAR) use. Method Carbapenem days of therapy (CAR-DOT) were calculated to assess the effect of each intervention, and antipseudomonal DOT were calculated to assess changes in use of broad-spectrum antibiotics. We carried out segmented regression analysis of studies with interrupted time series for 3 periods: Phase 1 (infectious disease [ID] consultation service only), Phase 2 (adding monitoring and e-mail feedback), and Phase 3 (adding postprescription review and feedback [PPRF] led by ID specialist doctors and pharmacists). We also estimated cost savings over the study period due to decreased CAR use. Results The median monthly CAR-DOT, per month per 100 patient-days, during Phase 1, Phase 2, and Phase 3 was 5.46, 3.69, and 2.78, respectively. The CAR-DOT decreased significantly immediately after the start of Phase 2, but a major decrease was not observed during this period. Although the immediate change was not apparent after Phase 3 started, CAR-DOT decreased significantly over this period. Furthermore, the monthly DOT of 3 alternative antipseudomonal agents also decreased significantly over the study period, but the incidence of antimicrobial resistance did not decrease. Cost savings over the study period, due to decreased CAR use, was estimated to be US $150 000. Conclusions Adding PPRF on the conventional ASP may accelerate antimicrobial stewardship. Our CAR stewardship program has had positive results, and implementation is ongoing.