Provincial and Temporal Variation in Macrolide and Lincosamide Antimicrobial Use by Outpatients in Canada, 1995 to 2010

INTRODUCTION: Because antimicrobial use is commonly associated with the development of antimicrobial resistance, monitoring the volume and patterns of use of these agents is very important.OBJECTIVE: To assess the use of macrolide and lincosamide (ML) antimicrobials within Canadian provinces over time, and to compare use rates with those reported by European countries.METHODS: Antimicrobial prescribing data were used to develop two yearly metrics: prescriptions per 1000 inhabitant-days (PrIDs) and the mean defined daily doses (DDDs) per prescription, which were then used to build linear mixed models to assess differences among provinces over time.RESULTS: After accounting for repeated measures over time, prescribing rates (PrIDs) varied significantly according to province and year (P<0.001). However, little change occurred within each province over the time frame studied; from 1995 to 2010, each province had a PrID change <0.01. Quebec and British Columbia had significantly lower prescribing rates than all other provinces. No overall secular trend was apparent. In contrast, the DDDs per prescription did not vary significantly according to province, but showed a significant year-to-year increase.DISCUSSION: ML prescribing varied among provinces in Canada between 1995 and 2010, but remained relatively stable within each province. The average DDDs per ML prescription did not vary according to province, but increased linearly over time. These increases are likely to indicate that fewer prescriptions are being written for children over time, a practice supported by good antimicrobial stewardship principles.