Abstract
This quasi-experimental study aimed to investigate the changes in antibiotic use tailored by adjusting provincial antibiotic restriction lists in China using interrupted time-series analysis from 2013 to 2019. Antibiotic use was assessed as defined daily dose (DDD) per 1000 patients per day. Trends and level changes were analysed with segmented regression. The study identified 19 antibiotic formulations in four provinces with adjusted restriction levels (intervention group) and 110 formulations in the rest provinces without adjustments (comparison group). Antibiotics restriction level changed between two categories: (1) between 'highly-restricted' and 'restricted' and (2) between 'restricted' and 'non-restricted'. Analysis revealed distinct trend changes for antibiotics moving between 'highly-restricted' and 'restricted' (β = 0.0211, P = 0.003) and 'restricted' to 'highly-restricted' (β = -0.0039, P = 0.128) compared to the comparison group. After a 2-y adjustment period, when moving from 'restricted' to 'highly-restricted', absolute antibiotic utilisation significantly decreased (P < 0.001), with a relative decrease of 100.8% (P < 0.001) compared to the comparison group. Besides, individual antibiotics with higher consumption displayed greater responsiveness to adjustment. These findings underscore the changes in restriction level adjustments on antibiotics, highlighting antibiotic restriction list policies as crucial tools for antimicrobial stewardship.