Comparison of the Efficacy of Empagliflozin, Dapagliflozin, and Allopurinol Based on Serum Uric Acid Levels and Kidney Function in Patients with Type 2 Diabetes Mellitus: A Retrospective Cohort Study.

Background

Type 2 diabetes mellitus (T2DM) is often associated with hyperuricemia, both conditions worsening kidney function. Sodium-glucose cotransporter 2 (SGLT2) inhibitors improve glycemic control and kidney function; however, data on their long-term antihyperuricemic effects in real-world clinical settings remain limited. Therefore, we aimed to compare the effects of SGLT2 inhibitors versus allopurinol on serum uric acid (sUA), kidney function, and clinical outcomes.

Methods

This retrospective cohort study evaluated patients with T2DM and hyperuricemia initiated on 10 mg empagliflozin (n = 70), 10 mg dapagliflozin (n = 78), or 100 mg allopurinol (n = 66) between 1 January 2017, and 1 January 2020. Drug dosages were kept constant throughout the study. Baseline and follow-up data (3, 6, 12, 24, and 36 months) were collected.

Results

Over 36 months, empagliflozin and dapagliflozin significantly reduced sUA (from 452 (95) to 399 (69) µmol/L and from 450 (81) to 364 (71) µmol/L, respectively) and stabilized eGFR without a significant decline. Allopurinol also reduced sUA (from 430 (89) to 345 (69) µmol/L) but was associated with a progressive eGFR decline (from 70 (35) to 57 (32) mL/min/1.73 m2). Mortality was the highest in the allopurinol group; however, therapy discontinuation was the lowest with this treatment.

Conclusions

SGLT2 inhibitors achieved comparable sUA reduction to allopurinol by 36 months while preserving eGFR. Allopurinol was associated with higher mortality and hospitalization rates; SGLT2 inhibitor therapy was associated with favorable multidomain outcomes, but strategies to address adverse effects are needed to enhance adherence.