Effect of discontinuation of an antimicrobial stewardship programme on the antibiotic usage pattern

This study aimed to analyse the effect of discontinuation of antimicrobial stewardship programme (ASP) activity on the usage pattern of antibiotics. An interrupted time-series analysis assessing the trends in antibiotic use was conducted between September 2015 and August 2019 in an 859-bed university-affiliated hospital in Korea, where all ASP activities were discontinued in March 2018. The major activity of the ASP was a restrictive antibiotic programme. The use of restrictive antibiotics increased immediately after the discontinuation of the ASP by 41.06 days of therapy (DOT)/1000 patient-days in the general ward (95% confidence interval (CI) 21.04–61.08) and by 391.04 DOT/1000 patient-days in the intensive care unit (ICU) (95%CI 207.56–574.51). In addition, there were positive changes in the slope for the use of restrictive antibiotics in the general ward (7.06 DOT/1000 patient-days per month, 95%CI 4.63–9.50) and ICU (35.95 DOT/1000 patient-days per month, 95%CI 18.70–53.19). The use of broad-spectrum antibiotics in the general ward significantly decreased (–87.54 DOT/1000 patient-days, 95%CI –149.29 to –25.79). For non-broad-spectrum antibiotics, there were positive changes in the slope in the general ward (16.54 DOT/1000 patient-days per month, 95%CI 12.99–20.09) and ICU (12.85 DOT/1000 patient-days per month, 95%CI 2.32–23.38). After discontinuation of the ASP, antibiotic usage patterns rapidly returned to the patterns prior to the implementation of the programme.