Use of Sodium-Glucose Cotransporter-2 Inhibitors in Adults Aged ≥65 Years With Type 2 Diabetes and Cardiovascular Disease: A Cross-sectional Study of Different Drug Funding Policies

Objectives

Sodium-glucose cotransporter-2 inhibitors (SGLT2is) provide heart and kidney benefits in adults with diabetes and cardiovascular disease (CVD). Public drug coverage policies for SGLT2is differ by province in Canada. In this study, we describe the potential effects of prior authorization/step therapy (PA/ST) and relatively high income-based deductibles, compared with regular benefit status with modest copay, on SGLT2i prescriptions in high-risk adults.

Methods

This investigation was a cross-sectional study of adults ≥65 years of age with type 2 diabetes and CVD and taking at least 1 antihyperglycemic agent from 2019 to 2020. Using electronic medical record data obtained from primary care practices, we compared SGLT2i use (2019 to 2020) in Alberta (PA/ST, modest copay) and Manitoba (PA/ST, relatively high income-based deductible) vs Ontario (regular benefit status, modest copay). Poisson regression was used to adjust for confounders, including age, sex, glycated hemoglobin, and other medication use. Other diabetes medications were estimated as control cases.

Results

We included 3,191 adults (average age 75 years, 31% women). SGLT2i use was lowest in Manitoba (15.6%), followed by Alberta (25.9%), and highest in Ontario (31.9%). After adjustment, compared with Ontario, SGLT2i prescriptions were lower in Alberta (prevalence ratio [PR] 0.80, 95% confidence interval [CI] 0.71 to 0.91, p<0.001) and Manitoba (PR 0.48, 95% CI 0.39 to 0.59, p<0.001).

Conclusions

PA/ST and relatively high deductibles are associated with reduced SGLT2i prescribing---PA/ST by approximately 20% in Alberta and Manitoba, and relatively high deductibles by an additional relative reduction of 40% in Manitoba. PA/ST and cost-sharing policies should be flexible and responsive to changing evidence of clinical benefit.