Impact evaluation of guidelines on antibiotic utilisation & appropriateness in Malaysian public primary care: an interrupted time series analysis.

Background: The National Antimicrobial Guidelines (NAG) 2014 and NAG2019 in Malaysia targeted rational and judicious use of antimicrobials. In this study, we assessed the change in antibiotic utilisation and appropriateness due to the guidelines that were implemented from 2011 to 2019.

Methods: Interrupted time series analyses on rates of antibiotic appropriateness and utilisation were performed using prescription data from public primary care clinics in Malaysia between January 2011 and December 2019. Rates of antibiotic utilisation, reported as Defined Daily Dose (DDD) per 1000 patients per day, were stratified by antibiotic classes.

Results: Of the 16,081,492 prescriptions recorded during the study period, 4.98% (n = 800,899) contained antibiotics. NAG2014 resulted in a significant increase in antibiotic utilisation trend by 0.029 (p < 0.0001) while NAG2019 had a substantial impact on antibiotic utilisation, decreasing DDD by 1778 and increasing appropriateness by 54.6% (p < 0.0001). Variation in the number of antibiotic molecules being prescribed also decreased after NAG2019.

Conclusion: Our findings indicate that the introduction of NAG2019 led to a substantial improvement in antibiotic appropriateness. At the same time, antibiotic utilisation decreased. Further research is needed to ascertain and ensure the sustainability of these changes and to establish targeted improvement strategies focusing on reducing inappropriate and unnecessary prescribing.