A population-based analysis of antidiabetic medications in four Canadian provinces: Secular trends and prescribing patterns

Abstract

Purpose: To use the Canadian Network for Observational Drug Effect Studies (CNODES) to describe drug utilization of antidiabetic medications in four Canadian provinces.

Methods: With the use of data from CNODES, we constructed cohorts of patients with type 2 diabetes in four Canadian provinces (Manitoba, Ontario, Quebec, and Saskatchewan) who received their first-ever prescription for a noninsulin antidiabetic medication during the study period, defined as the earliest date of data availability in each province (range: 1993-1998) to the latest date of the data extraction in each province (range: 2013-2014). Prescriptions rates were calculated for all prescriptions by class and described over time.

Results: Across provinces, we identified 650 830 patients who initiated antidiabetic medications during the study period. In most provinces, the overall prescription rate of antidiabetic medications increased during the last two decades. Metformin particularly increased in popularity, surpassing sulfonylureas in all provinces as the most widely prescribed antidiabetic medication by the early 2000s. Thiazolidinediones grew in popularity from the onset of their availability until 2006 to 2007, at which point they rapidly declined. Dipeptidyl peptidase-4 inhibitors saw substantial growth in several provinces following their addition to provincial formularies in 2008 to 2012, while glucagon-like peptide-1 agonists experienced modest growth. Insulin prescription rates remained constant or steadily increased over the last two decades.

Conclusions: CNODES can be used for cross-jurisdictional drug utilization studies. In Canada, trends in antidiabetic medication prescriptions followed changing guidelines reflecting up-to-date knowledge of drug effectiveness and safety.

Keywords: Canada; antidiabetic; antihyperglycemic; diabetes; drug utilization; pharmacoepidemiology; prescribing patterns.