Kidney Stones: Do Hydration Targets Prevent Recurrence?

A large-scale clinical trial has cast doubt on the effectiveness of intensive hydration programs in preventing the recurrence of kidney stones, despite participants increasing their urine output. The findings, published March 19 in The Lancet, suggest that simply drinking more water may not be enough to address the complex issue of kidney stone formation.

The study, coordinated by the Duke Clinical Research Institute and involving researchers from institutions including Children’s Hospital of Philadelphia and the University of Washington, enrolled 1,658 adolescents and adults between 2017 and 2024. Participants, all with a history of kidney stones, were randomly assigned to either standard care or a behavioral hydration program. The program utilized Bluetooth-enabled smart water bottles to track fluid intake, personalized hydration goals – termed “fluid prescriptions” – financial incentives, reminder texts, and health coaching.

While the behavioral program successfully increased urine output among participants, the increase was described as modest. More significantly, the increased hydration did not translate into a reduction in the rate of symptomatic kidney stone recurrence compared to those receiving standard care, according to researchers. The study represents the largest health behavior intervention trial ever conducted for kidney stone prevention.

“The trial results indicate that despite the importance of high fluid intake to prevent stone recurrence, achieving and maintaining extremely high fluid intake is more challenging than we often assume for people with urinary stone disease,” said Charles Scales, M.D., associate professor in the departments of Urology and Population Health Sciences at Duke University School of Medicine, and a co-senior author of the study. “The challenge of adherence likely contributes to the relatively high rate of stone recurrence in people with this chronic condition.”

Kidney stones affect approximately 1 in 11 people in the United States, and nearly half experience a recurrence. The condition can cause severe pain and frequently leads to emergency room visits. Increasing fluid intake has long been a universally recommended strategy to reduce the risk of stone formation.

Gregory E. Tasian, M.D., Director of the PKIDS Care Improvement Network at CHOP, emphasized the importance of studying prevention approaches in adolescents, noting that prior to this trial, large-scale clinical trials focusing on kidney stone prevention in this age group were lacking. “It was important to test the effectiveness of strategies to increase adherence to a cornerstone of prevention of symptomatic stone event for patients across the lifespan, including those whose disease began in childhood,” Tasian said.

Researchers acknowledge the findings highlight the difficulties patients face in consistently meeting recommended fluid intake levels, even with structured support. Dr. Jonathan Harper, professor of urology at the University of Washington School of Medicine, stated, “We grasp hydration is fundamental in reducing kidney stones, but this trial highlights how challenging it may be to change behavior and drink enough to achieve urine-volume goals.”

The study’s findings suggest a need for renewed methods of kidney stone prevention, as the current emphasis on increased hydration alone may be insufficient for many patients. Further research is needed to identify alternative or complementary strategies to address the underlying factors contributing to kidney stone recurrence.