LAUSR

Adverse kidney outcomes, including acute kidney injury (AKI), are frequent complications in people with diabetes mellitus type 2. In large placebo-controlled randomized trials, both sodium-glucose cotransporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP1-RA) have shown efficacy in reducing the risk of kidney outcomes; however, no trial has compared the kidney protective effects of these drug classes head-to-head. We therefore conducted an emulated target trial to compare the effect of SGLT2i to that of GLP1-RA on the incidence of AKI. Using routinely collected data from nationwide Danish population-based registries, we included all adults with diabetes mellitus type 2 initiating SGLT2i or GLP1-RA in 2015-2020. Patients with prevalent kidney failure (defined as eGFR < 15 mL/min/1.73m2, dialysis, or kidney transplant), and patients initiating GLP1-RA marketed specifically for treatment of obesity were excluded. We assessed demographic and diabetes-related baseline characteristics along with comorbidities and comedication. We used propensity scores, estimated by logistic regression, to compute stabilized inverse probability of treatment weights, which were applied in all analyses to reduce confounding. Using an intention to treat approach, we followed patients from treatment initiation until the first of death, emigration, or end of follow-up (31 December 2021). Using creatinine measurements from in- and outpatient settings, we applied the KDIGO definition of AKI to record each episode of AKI during follow-up. We estimated the risk of a first AKI episode over time using the Aalen-Johansen estimator. Furthermore, to estimate the mean number of AKIs over time, i.e., including recurrent AKIs, we used the mean cumulative count estimator. Both estimators account for the competing risk of death. Comparing SGLT2i to GLP1-RA, we reported differences in risks and counts at 1, 3 and 5 years of follow-up. Finally, we estimated all-cause mortality using the Kaplan-Meier estimator. We used bootstrapping to obtain 95% confidence intervals (95% CI). We included 68 010 individuals, of which 44 034 (65%) initiated SGLT2i, and 23 976 (35%) initiated GLP1-RA. Initiators of SGLT2i were slightly older (median age 63 vs 62 years) and more often male (63% vs 56%) than initiators of GLP1-RA, but with similar diabetes duration (7 vs 7 years). The annual number of initiators of each drug in Denmark increased over the study period. Compared to GLP1-RA, initiators of SGLT2i generally had better estimated glomerular filtration rate (eGFR) at baseline (9% vs 18% had eGFR < 60 mL/min/1.73m2), more frequently used metformin (91% vs 84%), but less frequently insulin (11% vs 28%). Initiators of SGLT2i had a lower prevalence of hospital-diagnosed retinopathy (7% vs 9%), neuropathy (5% vs 6%), and obesity (13% vs 23%) than initiators of GLP1-RA. After inverse probability of treatment weighting, each variable was well balanced with absolute standardized mean differences below 0.02. During a median follow-up of 2.8 years, the weighted absolute risks of first time AKI at 1, 3, and 5 years were 4.8%, 11.2%, and 17.0% for initiators of SGLT2i, and 5.4%, 12.3%, and 19.1% for initiators of GLP1-RA, resulting in AKI risk differences of −0.6% (95% CI: −1.0% to −0.3%), −1.0% (95% CI: −1.7% to −0.5%), and −2.0% (95% CI: −3.0% to −1.1%). The mean cumulative counts showed a similar pattern, with SGLT2i initiators experiencing slightly fewer AKI episodes than GLP1-RA initiators on average (Fig. 1). After 5 years, an estimated 10.3% of SGLT2i initiators and 9.6% of GLP1-RA initiators had died, resulting in a risk difference of 0.7% (95% CI: -0.1% to 1.5%). People with diabetes mellitus type 2 who initiated SGLT2i had slightly lower weighted incidence of AKI over 5 years than those initiating GLP1-RA.