In a two-year U.S. trial of 1,658 adolescents and adults with prior kidney stones, a technology-assisted hydration program modestly increased urine output but did not significantly reduce symptomatic stone recurrences compared with standard care.
Researchers from the Urinary Stone Disease Research Network reported results from a large randomized clinical trial testing whether a structured, behavior-focused hydration program could prevent kidney stones from returning.
The study enrolled 1,658 adolescents and adults at six U.S. clinical centers: UT Southwestern Medical Center, Washington University in St. Louis, the University of Pennsylvania/Children’s Hospital of Philadelphia, the University of Washington, Mayo Clinic, and Cleveland Clinic. Participants were randomly assigned to standard care or an intensive behavioral hydration program.
The intervention included Bluetooth-enabled “smart” water bottles to track fluid intake, personalized “fluid prescriptions” designed to reach a urine output goal of at least 2.5 liters per day, along with text reminders, health coaching, and financial incentives. Investigators followed participants for two years, using regular surveys and imaging to assess symptomatic kidney stone recurrence and whether new stones formed or existing stones grew.
The findings, published in The Lancet (March 2026), showed that while participants in the intervention group increased average urine output, the improvement was not sufficient to significantly reduce symptomatic stone-recurrence rates across the overall study population.
“The trial results show that despite the importance of high fluid intake to prevent stone recurrence, achieving and maintaining very high fluid intake is more challenging than we often assume for people with urinary stone disease,” said Charles Scales, M.D., an associate professor at Duke University School of Medicine and a co-senior author.
Gregory E. Tasian, M.D., co-senior author and principal investigator at Children’s Hospital of Philadelphia, said the results support more individualized approaches.
“Across adolescents and adults, the study moves the field toward more precise prevention,” Tasian said, arguing that researchers should determine which patients benefit from which hydration targets and develop interventions that reliably reduce recurrences.
Alana Desai, M.D., the study’s first author and a Washington University in St. Louis investigator, described kidney stone disease as “a chronic condition, punctuated by unpredictable, sometimes excruciatingly painful episodes” that can disrupt daily life.
Kidney stones affect an estimated about 1 in 11 people in the United States, and nearly half experience a recurrence, according to the study authors and participating institutions.
Funding for the trial was provided by the National Institute of Diabetes and Digestive and Kidney Diseases, the researchers said.
