Appropriateness of Outpatient Antibiotic Use in Seniors across Two Canadian Provinces

Abstract

Antimicrobials are among the most prescribed medications in Canada, with over 90% of antibiotics prescribed in outpatient settings. Seniors prescribed antimicrobials are particularly vulnerable to adverse drug events and antimicrobial resistance. The extent of inappropriate antibiotic prescribing in outpatient Canadian medical practice, and the potential long-term trends in this practice, are unknown. This study is the first in Canada to examine prescribing quality across two large-scale provincial healthcare systems to compare both quantity and quality of outpatient antibiotic use in seniors. Population-based analyses using administrative health databases were conducted in British Columbia (BC) and Ontario (ON), and all outpatient, oral antimicrobials dispensed to seniors (≥65 years) from 1 January 2000 to 31 December 2018 were identified. Antimicrobials were linked to an indication using a 3-tiered hierarchy. Tier 1 indications, which always require antibiotics, were given priority, followed by Tier 2 indications that sometimes require antibiotics, then Tier 3, which never require antibiotics. Prescription rates were calculated per 1000 population, and trends were examined overall, by drug class, and by patient demographics. Prescribing remained steady in both provinces, with 11,166,401 prescriptions dispensed overall in BC, and 27,656,014 overall in ON. BC prescribed at slightly elevated rates (range: 790 to 930 per 1000 residents), in comparison to ON (range: 745 to 785 per 1000 residents), throughout the study period. For both provinces, a Tier 3 diagnosis was the most common reason for antibiotic use, accounting for 50% of all indication-associated antibiotic prescribing. Although Tier 3 indications remained the most prescribed-for diagnoses throughout the study period, a declining trend over time is encouraging, with much room for improvement remaining. Elevated prescribing to seniors continues across Canadian outpatient settings, and prescribing quality is of high concern, with 50% of all antimicrobials prescribed inappropriately for common infections that do not require antimicrobials.

Search for Indexes to Evaluate Trends in Antibiotic Use in the Sub-Prefectural Regions Using the National Database of Health Insurance Claims and Specific Health Checkups of Japan

“…Differences in AMUs at the regional level have been reported in other countries, such as the United States and Germany [ 26 , 27 , 28 , 29 ]. In both cases, regional units are defined according to the situation in each country so that the effectiveness of AMR measures can be more effectively evaluated.…”

Look-Back and Look-Forward Durations and the Apparent Appropriateness of Ambulatory Antibiotic Prescribing

“…Ambulatory antibiotic stewardship programs and research projects can select a duration of association that makes sense for their purposes. For example, if the intent is to identify and intervene on inappropriate diagnoses, then the use of a short interval–even same-day–is reasonable, as the proportion of prescriptions classified as inappropriate varies minimally based on the look-back and look-forward periods [ 11 , 19 , 20 , 21 , 22 ]. If the intent is to intervene on potentially appropriate antibiotic prescribing, using longer durations will capture a larger number of these diagnoses [ 23 , 24 , 25 ].…”

“…Owing in part to the lack of prior literature on the impact of these choices on assessments of antibiotic appropriateness, prior antibiotic prescribing studies and performance measurement programs have used widely varying look-back and look back-and-forward durations, such as 1 day [ 1 ], 2 days [ 2 , 3 , 4 ], 3 days [ 5 , 6 , 7 , 8 , 9 , 10 ], 5 days [ 11 ], 7 days [ 12 , 13 , 14 ], and 30 days [ 15 ]. The impact of these choices on the seeming appropriateness of antibiotic prescribing is unclear and, to our knowledge, has not been previously examined.…”

Retrospective cohort analysis of outpatient antibiotic prescribing for community-acquired pneumonia in Canadian older adults

“…In BC, doxycycline accounted for a much larger proportion of prescriptions issued (43%), when compared to Ontario (4%). Previous work by this team had identified a provincial difference in tetracycline prescription, with BC using six times more than Ontario [35]. A potential explanation for this inter-provincial difference may be the shift to tetracyclines as a preferred agent in BC clinical resources, while beta-lactams remain primary agents in Ontario.…”