Empagliflozin Induces Transient Diuresis Without Changing Long-Term Overall Fluid Balance in Japanese Patients With Type 2 Diabetes

Introduction: Empagliflozin, a sodium glucose co-transporter 2 (SGLT2) inhibitor, ameliorates hyperglycemia in patients with type 2 diabetes (T2D) by inducing sustained glucosuria. Empagliflozin treatment was previously associated with a transient increase in 24-h urine volume in Caucasian patients with T2D, however comparable evidence in Japanese T2D individuals is scarce. We therefore assessed acute and chronic changes in 24-h urine volume and fluid intake with empagliflozin in Japanese patients with T2D. Methods: In this randomized, double-blind, placebo-controlled, parallel-group, multipledose, 4-week trial, 100 Japanese patients with T2D were randomized to receive either 1, 5, 10, or 25 mg empagliflozin or placebo once-daily. Changes from baseline in 24-h urine volume and fluid intake were assessed at days 1, 27, and 28 after the initiation of empagliflozin. Results: The 24-h urine volume and fluid intake were comparable across all treatment groups at baseline. Patients treated with either 10 or 25 mg empagliflozin (i.e., the licensed doses in Japan) showed a significant increase in 24-h urine volume compared to placebo at day 1 (mean change from baseline: + 0.83, + 1.08, and + 0.29 L/day in the empagliflozin 10 and 25 mg groups and the placebo group, respectively; both p < 0.001 vs. placebo). However, 24-h urine volume levels in the empagliflozin groups were comparable to placebo at day 27 and 28 (differences vs placebo < 0.1 L/day; p > 0.05). The 24-h fluid intake was comparable across all study groups throughout the entire study period. No events consistent with dehydration were reported during empagliflozin treatment. Conclusion: Treatment initiation with empagliflozin in Japanese patients with T2D was associated with transient diuresis; however, overall urine volume returned towards baseline levels within 4 weeks of treatment. These findings are consistent with a physiological, adaptive mechanism of the kidney to maintain overall body fluid balance in response to treatment initiation with a SGLT2 inhibitor.