Increased fluid intake is universally recommended to decrease the risk of recurrent urinary stones; however, adherence is challenging. The effectiveness of interventions to maintain high fluid intake has not been well studied. We sought to determine whether a multicomponent behavioural intervention programme to promote high fluid intake reduces symptomatic stone recurrence, compared with a control.
In this randomised clinical trial, participants aged 12 years and older with a history of urinary stone disease and low 24 h urine volumes based on current guidelines were enrolled at six academic medical centres in the USA. Participants were randomly assigned in a 1:1 ratio to a multicomponent behavioural intervention designed to promote increased fluid intake or to the control group receiving guideline-concordant care. The intervention consisted of a fluid prescription, financial incentives to adhere to fluid prescription, health coaching to overcome barriers to consuming more fluids, and patient-selected approaches such as text messaging to maintain increased fluid intake. Randomisation assignment was computer-generated remotely, and investigators, treating physicians, outcome assessors, and adjudicators were masked to group assignment. The primary outcome was symptomatic stone recurrence defined as stone passage or procedural intervention for stone(s) during a 2-year follow-up period, analysed in the intention-to-treat population. Secondary outcomes included change in 24 h urine volume, urinary symptoms, radiographic stone recurrence or growth, and a composite outcome of symptomatic stone recurrence, new stone formation, and growth of existing stone(s); hyponatremia requiring hospitalisation was the safety endpoint. This trial is registered with ClinicalTrials.gov, NCT03244189.
Between Oct 26, 2017, and Feb 18, 2022, 1658 participants were randomly assigned to intervention (n=826) and control (n=832) groups (median age 44 years [IQR 29-59]; 946 [57%] female). At a median follow-up of 738 days (IQR 711-778), symptomatic stone events occurred in 154 (19%) participants in the intervention group and 165 (20%) in the control group (hazard ratio 0·96, 95% CI 0·77-1·20). Among these 1658 participants, 1104 (66·6%) were recurrent stone formers. 24 h urine volume increased from baseline in both groups and was higher in the intervention group at months 6, 12, 18, and 24 compared with the control group. Urinary storage symptoms of frequency, urgency, and nocturia were greater in the intervention group versus control at months 6 and 12 but not at other timepoints. There was no difference in stone growth of at least 2 mm or new stones between groups from baseline to end-of-study imaging, and the composite outcome of symptomatic stone recurrence, new stone formation, or stone growth of at least 2 mm was also not statistically different between groups. No episodes of hyponatremia requiring hospitalisation (safety endpoint) were reported; 12 (1%) participants in the intervention group had asymptomatic hyponatraemia versus two (<1%) participants in the control group.
A behavioural intervention programme to promote fluid intake for secondary stone prevention did not reduce recurrent stone events but modestly increased urine volume compared with guideline-based care during a 2-year follow-up period.
National Institute of Diabetes and Digestive and Kidney Diseases.
Lancet (London, England). 2026 Mar 21 [Epub]
Alana C Desai, Naim M Maalouf, Jonathan D Harper, Sri Sivalingam, John C Lieske, H Henry Lai, Peter P Reese, Hunter Wessells, Hongqiu Yang, Hussein R Al-Khalidi, Ziya Kirkali, Gregory E Tasian, Charles D Scales, Urinary Stone Disease Network Investigators
Department of Surgery, Division of Urology, Washington University in St Louis, St Louis, MO, USA., Department of Internal Medicine and Charles & Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA., Department of Urology, University of Washington School of Medicine, Seattle, WA, USA., Glickman Urological & Kidney Institute, Cleveland Clinic Foundation, Cleveland, OH, USA., Department of Nephrology and Hypertension, Mayo Clinic Foundation, Rochester, MN, USA., Department of Surgery, Division of Urology, Washington University in St Louis, St Louis, MO, USA; Department of Anesthesiology, Washington University in St Louis, St Louis, MO, USA., Division of Renal Electrolyte and Hypertension, Department of Medicine, Perlman School of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA., Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA., Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA; Department of Biostatistics & Bioinformatics, Duke University School of Medicine, Durham, NC, USA., National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA., Children's Hospital of Philadelphia, Philadelphia, PA, USA., Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA; Departments of Urology and Population Health Science, Duke University School of Medicine, Durham, NC, USA. Electronic address: .