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

Objectives: This study aimed to analyse the effect of discontinuation of antimicrobial stewardship programme (ASP) activity on the usage pattern of antibiotics. Methods: 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. Results: 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). Conclusions: After discontinuation of the ASP, antibiotic usage patterns rapidly returned to the patterns prior to the implementation of the programme.