Socioeconomic position and initiation of SGLT-2 inhibitors or GLP-1 receptor agonists in patients with type 2 diabetes – a Danish nationwide observational study

Abstract Background Between 2015 and 2017, Sodium-glucose cotransporter-2 (SGLT-2) inhibitors and glucacon-like-peptide-1 receptor agonists (GLP-1 RA) were shown to reduce cardiovascular events in patients with type 2 diabetes and cardiovascular disease. Thus, in 2018, guidelines were updated to favor these drugs in patients with cardiovascular disease and type 2 diabetes. Lower socioeconomic position may adversely affect use of SGLT-2 inhibitors and GLP-1 RA. Purpose We aimed to examine socioeconomic differences in initiation of SGLT-2 inhibitors and GLP-1 RA in a contemporary population of patients with type 2 diabetes. Methods Through the Danish nationwide registers, we identified all patients with type 2 diabetes who initiated second-line add-on therapy after metformin monotherapy between December 10, 2012, and December 31, 2018. Patients aged 40–79 years and without a history of end-stage renal disease were included. We measured socioeconomic position according to level of income: Low = 1st quartile; Middle = 2nd and 3rd quartile; High = 4th quartile. Based on multivariable logistic regression models adjusted for age, sex, cohabitation status, duration of type 2 diabetes, comorbidities, and cardiovascular medications, we reported the standardised probabilities of initiating each drug class at time of first intensification according to income group and time period: 2012–2014, 2015–2017, and 2018. Results The 33,201 patients had a median age of 63 years (interquartile range 53–69). The probability of initiating a SGLT-2 inhibitor or a GLP-1 RA increased over time in all income-groups. In each time period, the standardised probability of initiating a SGLT-2 inhibitor or a GLP-1 RA at time of first intensification increased with increasing income (Figure): in 2012–2014, from 9.6% (95% confidence interval (CI) 8.4–10.9) in the lowest income group to 14.4% (CI 12.9–15.9) in the highest income group; in 2015–2017, from 19.5% (CI 18.3–20.7) to 24.6% (CI 23.3–25.9); in 2018, from 39.9% (CI 37.5–42.3) to 50.7% (CI 48.2–53.1). The absolute difference between high and low income groups increased over time, reaching 10.8% (CI 7.3–14.3) in 2018. A similar trend was observed in both subgroups of patients with and without established cardiovascular disease (data not shown). Initiation of a dipeptidyl peptidase-4 (DPP-4) inhibitor increased with income in the early time periods, but this trend reversed in 2018 (Figure). Initiation of sulfonylureas (SU) showed a consis