A novel clinical investigation has revealed promising results for empagliflozin in the prevention of kidney stones among non-diabetic individuals, potentially expanding the therapeutic applications of this SGLT2 inhibitor beyond diabetes management.
The SWEETSTONE trial, conducted at the Department of Nephrology and Hypertension at Bern University Hospital, Switzerland, evaluated empagliflozin's effects through a rigorous phase 2 randomized, double-blind, placebo-controlled crossover design. The study focused on two distinct patient populations: those with calcium stones and those with uric acid stones.
Study Design and Patient Population
Participants included non-diabetic adults aged 18-75 years who had experienced at least one previous kidney stone event. The trial specifically enrolled patients whose most recent kidney stones contained either ≥80% calcium or ≥80% uric acid. Notably, the study excluded individuals with secondary causes of kidney stones, chronic kidney disease, or those taking medications that could interfere with kidney stone formation.
The investigation followed a crossover design where patients received either empagliflozin 25mg daily or placebo for 14 days, followed by a 2-6 week washout period before switching to the alternate treatment. This design allowed for direct comparison of treatment effects within the same individual.
Key Findings and Clinical Implications
The study measured urinary relative supersaturation rates (RSRs) for calcium oxalate, calcium phosphate, and uric acid as primary outcomes. These measurements are crucial as they serve as reliable predictors of kidney stone formation risk. Previous research has shown that even a 15% reduction in urinary RSR for calcium oxalate can translate to approximately 12% reduction in stone recurrence risk.
Patients underwent comprehensive monitoring, including:
- 24-hour urine collection for detailed analysis
- Blood parameter measurements
- Safety assessments for adverse events
- Monitoring of vital signs and body weight
Safety and Compliance
Treatment compliance was verified through pill counts and urinary glucose monitoring during the empagliflozin treatment period, with values above 50 mmol per 24 hours indicating proper medication adherence. The study maintained rigorous blinding procedures throughout the trial period, with unblinding occurring only after the completion of primary analysis.
Future Implications
This research represents a significant step forward in understanding alternative applications for SGLT2 inhibitors, particularly in the field of kidney stone prevention. The findings could potentially lead to new therapeutic strategies for patients prone to kidney stone formation, especially those who cannot tolerate or have failed conventional preventive measures.
The study's robust design and careful patient selection provide valuable insights into empagliflozin's potential role in kidney stone prevention, though larger phase 3 trials would be needed to confirm these findings and establish clinical guidelines for this application.
