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

Background: Low socioeconomic position may affect initiation of sodium-glucose cotransporter-2 inhibitors (SGLT-2i) and glucacon-like-peptide-1 receptor agonists (GLP-1RA) among patients with type 2 diabetes (T2D). We examined the association between socioeconomic position and initiation of SGLT-2i or GLP-1RA in patients with T2D at time of first intensification of antidiabetic treatment. Methods: Through nationwide registers, we identified all Danish patients on metformin who initiated second-line add-on therapy between December 10, 2012, and December 31, 2020. For each time period (2012-2014, 2015-2017, and 2018-2020), we used multivariable multinomial logistic regression to associate disposable income, as proxy for socioeconomic position, with the probability of initiating a specific second-line treatment at time of first intensification. We reported probabilities standardised to the distribution of demographics and comorbidities of patients included in the last period (2018-2020). Findings: We included 48915 patients (median age 62 years; 61·7% men). In each time period, high-income patients were more often men and had less comorbidities as compared with low income-patients. In each time period, the standardised probability of initiating a SGLT-2i or a GLP-1RA was significantly higher in the highest income group compared with the lowest: 11·4% vs. 9·5% (probability ratio [PR] 1·21, 95 % confidence interval [CI] 1·01-1·44) in 2012-2014; 22·6% vs. 19.6% (PR 1·15, CI 1·05-1·27) in 2015-2017; and 65·8% vs. 54·8% (PR 1·20, CI 1·16-1·24) in 2018-2020. The differences by income were consistent across multiple subgroups. Interpretation: Despite a universal healthcare system, low socioeconomic position was consistently associated with a lower probability of initiating a SGLT-2i or a GLP-1RA. These disparities may widen the future socioeconomic gap in cardiovascular outcomes. Funding: The work was funded by unrestricted grants from ‘Region Sjaelland Den Sundhedsvidenskabelige Forskningsfond’ and ‘Murermester Lauritz Peter Christensen og hustru Kirsten Sigrid Christensens Fond’.