Use of SGLT-2 Inhibitors in Adults (Age ≥ 65) with Type 2 Diabetes and Cardiovascular Disease is Lower in Alberta and Manitoba than in Ontario (2018-2020): A Cross-Sectional Study of Different Drug Funding Policies.

Abstract

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

Methods: Cross-sectional study of individuals age ≥ 65 years with type 2 diabetes and CVD, taking ≥ 1 antihyperglycemic agent from 2019 to 2020, using electronic medical record data from primary care practices. We compared SGLT2i use (2019-2020) in Alberta (PA/ST, modest co-pay), and Manitoba (PA/ST, relatively high income-based deductible), to Ontario (regular benefit status, modest co-pay). 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% female). SGLT2i use was lowest in Manitoba (15.6%), then Alberta (25.9%), and highest in Ontario (31.9%). After adjustment, compared to Ontario, SGLT2i prescriptions were lower in Alberta (prevalence ratio [PR] 0.80, 95% CI [0.71-0.91], p < 0.001) and Manitoba (PR 0.48 [0.39-0.59], 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.