Prevention of Urinary Stones With Hydration (PUSH): Design and Rationale of a Clinical Trial

Am J Kidney Dis. 2021 Jun;77(6):898-906.e1. doi: 10.1053/j.ajkd.2020.09.016. Epub 2020 Nov 16.


Rationale & objective: Although maintaining high fluid intake is an effective low-risk intervention for the secondary prevention of urinary stone disease, many patients with stones do not increase their fluid intake.

Study design: We describe the rationale and design of the Prevention of Urinary Stones With Hydration (PUSH) Study, a randomized trial of a multicomponent behavioral intervention program to increase and maintain high fluid intake. Participants are randomly assigned (1:1 ratio) to the intervention or control arm. The target sample size is 1,642 participants.

Setting & participants: Adults and adolescents 12 years and older with a symptomatic stone history and low urine volume are eligible. Exclusion criteria include infectious or monogenic causes of urinary stone disease and comorbid conditions precluding increased fluid intake.

Interventions: All participants receive usual care and a smart water bottle with smartphone application. Participants in the intervention arm receive a fluid intake prescription and an adaptive program of behavioral interventions, including financial incentives, structured problem solving, and other automated adherence interventions. Control arm participants receive guideline-based fluid instructions.

Outcomes: The primary end point is recurrence of a symptomatic stone during 24 months of follow-up. Secondary end points include changes in radiographic stone burden, 24-hour urine output, and urinary symptoms.

Limitations: Periodic 24-hour urine volumes may not fully reflect daily behavior.

Conclusions: With its highly novel features, the PUSH Study will address an important health care problem.

Funding: National Institute of Diabetes and Digestive and Kidney Diseases.

Trial registration: Registered at with study number NCT03244189.

Keywords: RCT design; Urinary stone disease (USD); behavioral intervention; financial incentive; fluid prescription; health coaching; increased fluid intake; kidney disease prevention; kidney stone; lifestyle change; lower urinary tract symptoms; modifiable risk factor; randomized clinical trial (RCT); stone recurrence; urine volume.

Publication types

  • Clinical Trial Protocol
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adult
  • Drinking*
  • Humans
  • Randomized Controlled Trials as Topic / methods*
  • Urinary Calculi / prevention & control*

Associated data