Longitudinal Changes in Albuminuria and Estimated Glomerular Filtration Rate in Patients with Type 2 Diabetes Treated with Empagliflozin or Canagliflozin: A Real-World Cohort Study

Background: Direct real-world comparisons of empagliflozin and canagliflozin regarding renal outcomes in patients with type 2 diabetes mellitus (T2DM) remain limited. This study compared longitudinal changes in the estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (UACR). Methods: This retrospective observational cohort study included 215 adults with type 2 diabetes mellitus who received either empagliflozin (n = 115) or canagliflozin (n = 100) at a tertiary medical center. Renal outcomes, including estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR), were evaluated over 18 months. Between-group differences in renal outcomes were assessed using multivariable regression models adjusted for relevant baseline clinical characteristics. Linear mixed-effects models were additionally employed to account for repeated measurements and evaluate differences in longitudinal trajectories between treatment groups. A reduction in UACR of ≥30% from baseline was evaluated as a clinically meaningful albuminuria response using multivariable logistic regression. Subgroup analyses were performed according to age and baseline UACR. Results: In multivariable linear regression analysis, the 18-month change in eGFR did not differ significantly between canagliflozin and empagliflozin (adjusted β, −0.43 mL/min/1.73 m2; 95% confidence interval [CI], −4.12 to 3.26; p = 0.819). Consistently, linear mixed-effects models showed no significant treatment-by-time interaction for eGFR (p for interaction = 0.356) or log-transformed UACR (p for interaction = 0.104). In the adjusted logistic regression analysis, canagliflozin was associated with lower odds of achieving a ≥30% reduction in UACR at 12 months compared with empagliflozin (adjusted odds ratio [OR], 0.40; 95% CI, 0.20–0.79; p = 0.008). However, this association was not statistically significant at 18 months (adjusted OR, 0.62; 95% CI, 0.32–1.18; p = 0.147). Subgroup interaction analyses did not demonstrate significant effect modification by age or baseline UACR (p for interaction = 0.859 and 0.626, respectively). Conclusions: In this real-world cohort of patients with type 2 diabetes mellitus, empagliflozin and canagliflozin showed comparable longitudinal eGFR and UACR trajectories over 18 months. Although a difference in the likelihood of achieving a ≥30% reduction in UACR was observed at 12 months, this finding was not sustained at 18 months and should be interpreted cautiously. Overall, our findings do not establish the superiority of either SGLT2 inhibitor in terms of renal outcomes. Further studies with larger populations and prospective designs are warranted.