Impact of the Italian antimicrobial resistance National Action Plan on antibiotic consumption in primary care: An interrupted time series analysis from 1999 to 2024

OBJECTIVES: Antimicrobial resistance (AMR) is a major global health threat, largely driven by inappropriate and excessive antibiotic use. Italy has historically reported antibiotic consumption rates above the European average, especially in primary care. In 2017, Italy implemented the National Action Plan on Antimicrobial Resistance (NAP-AMR), including targets for reducing overall community antibiotic and fluoroquinolone use. This study evaluated the impact of NAP-AMR on antibiotic consumption trends in Italian primary care from 1999 to 2024. STUDY DESIGN: Quasi-experimental interrupted time series study. METHODS: Annual ECDC data were expressed as defined daily doses (DDD) per 1000 inhabitants per day. Total antibiotic consumption was analyzed for 1999-2024 and fluoroquinolone consumption for 2005-2024. Segmented linear regression with Newey-West standard errors estimated post-2017 changes in level and trend. Total systemic antibiotic consumption was the primary outcome, and fluoroquinolone consumption was the secondary outcome. RESULTS: Total antibiotic consumption showed a significant pre-intervention upward trend, increasing annually by 0.10 DDD per 1000 inhabitants per day (annual change = 0.096; p = 0.032; 95% CI: 0.014 to 0.178). NAP-AMR implementation was associated with a significant immediate reduction in total antibiotic use (mean level difference = -4.940; p = 0.003; 95% CI: -7.864 to -2.016), while the post-intervention slope change was not significant (annual change = 0.126; p = 0.606; 95% CI: -0.346 to 0.599). Fluoroquinolone consumption showed a significant pre-intervention upward trend (annual change = 0.039; p = 0.016; 95% CI: 0.011 to 0.066) and a significant immediate reduction (mean level difference = -1.079; p = 0.023; 95% CI: -1.910 to -0.248). The post-intervention trend was negative but not significant (annual change = -0.219; p = 0.096; 95% CI: -0.459 to 0.021). CONCLUSIONS: NAP-AMR was associated with immediate reductions in total antibiotic and fluoroquinolone consumption, but sustained trend changes were not statistically significant. No significant long-term trend change was observed, underscoring ongoing surveillance and future evaluation.