Smart water bottle trial aims to flush away kidney stones
NCT ID NCT03244189
First seen Jun 26, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Summary
This study tested whether a program to help people drink more water could prevent kidney stones from coming back. Over 1,600 adults and children who had a kidney stone in the past used a smart water bottle to track their intake, with some getting financial rewards for meeting their goals. The main goal was to see if this approach reduced the number of new stone events over two years.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- increased fluid intake (water) via a smart water bottle, with financial incentives and problem-solving support
- What this could lead to
- If it works, this could offer a simple, drug-free way to prevent painful kidney stones from returning.
- What could go wrong
- The trial is completed, but results may show only a modest benefit. Drinking more water is safe, but some people may find it hard to stick with the program long-term.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Not a phased trial
Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.
- Participants
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1,658 people
The number who actually took part.
- Started
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Oct 2017
- Finished
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May 2024
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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12 years and older
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 1. Aged ≥ 12 years 2. At least 1 symptomatic stone event (passage or procedural intervention) within 3 years prior to enrollment or a symptomatic stone event within 5 years if the patient also has new stone formation detected on imaging during the last 5 years. Symptomatic stone defined as any of the following: 1. Stone passage 2. Procedural intervention 3. Radiographically or ultrasonographically confirmed stone with any of the following: i. Gross hematuria ii. Renal colic or atypical abdominal pain attributed to the stone, as determined by a treating provider iii. A clinical pattern of intermittent symptoms consistent with intermittent obstruction at the ureteropelvic junction, as determined by a treating provider 3. Low 24-hr urine volume 1. ≥18 years old: \<2.0 L/day 2. \<18 years old: \<25 ml/Kg/day up to 2.0L/day 4. Able to provide informed consent (parental permission for children) 5. Owning and willing to use a smartphone or other device (e.g., tablet) compatible with the study-provided wireless enabled "smart" bottle Exclusion Criteria: 1. Spinal cord injury 2. Currently undergoing active treatment for cancer except basal cell skin cancer, or patients with a history of cancer who completed their initial therapy \<1 year before screening. 3. Known infectious (struvite), monogenic or other causes of stone disease for which therapies are likely to significantly alter course of stone disease 1. Cystinuria 2. Primary hyperoxaluria 3. Primary xanthinuria 4. Primary hyperparathyroidism 5. Sarcoidosis 6. Medullary sponge kidney 4. History or presence of hyponatremia (serum sodium \<130 mmol/L) or hypo-osmolality (serum osmolality \<275 mosm/kg) 5. Study participants with comorbidities that preclude high fluid intake or prior surgery precluding high fluid intake or leading to GI fluid losses 1. History of or current Crohn's disease, ulcerative colitis, short gut syndrome (e.g. ileostomy, bowel bypass surgery to treat obesity, small bowel resection), chronic diarrhea, or GI tract ostomy. 2. History of malabsorptive (e.g., Roux-en-Y gastric bypass) or restrictive (e.g., sleeve gastrectomy) bariatric surgery procedures 3. Congestive heart failure i. NYHA class II or greater, and/or ii. Hospital admission in the past year for heart failure d. Lung disease with a home oxygen requirement e. Chronic kidney disease (eGFR \<30 ml/min/1.7 m2 over a 3-month period) i. For adults (age ≥18), we will use the CKD-Epi equation which requires the measurement of serum creatinine only. ii. For children (age \<18), we will use the bedside Schwartz (CKiD) formula. f. Nephrotic syndrome (\>3.5 grams of protein per 24 hours) g. Cirrhosis with ascites 6. Women who are currently pregnant or planning pregnancy within 2 years. 7. Renal transplant recipient 8. Bedridden study participants (ECOG ≥ 3) 9. Uncorrected anatomical obstruction of the urinary tract 10. History of recurrent urinary tract infections (\> 3 UTI/year proven by urine culture) 11. Exclusions due to medication use: 1. Chronic use of lithium 2. Long-term glucocorticoid use (\> 7.5 mg prednisone daily for \> 30 days prior to enrollment) 3. Intake of narcotic medication on a daily basis for \>30 days prior to enrollment 4. Supplemental Vitamin C (\> 1 g daily) 12. Individuals with stones that have developed after the initiation of medications that are strongly associated with USD such as carbonic anhydrase inhibitors (acetazolamide, topiramate, zonisamide), high dose vitamin C (\> 1 g daily), high dose calcium supplementation (\> 1,200 mg daily) AND who have discontinued or plan to discontinue these medications. 13. Individuals with stones composed of medications that may crystallize in the urine (guaifenesin, sulfonamides, triamterene, and the protease inhibitors indinavir and nelfinavir) AND who have discontinued or plan to discontinue these medications. Note: Individuals who are on long-term medications that increase the risk of stone disease, who cannot stop these medications due to other chronic conditions (e.g., HIV) and who may reduce their risk for stone recurrence through increased fluid intake, will be eligible to participate in the trial. Examples of these medications include: 1. Carbonic anhydrase inhibitors (acetazolamide, topiramate, zonisamide) 2. Medications that may crystallize in the urine (guaifenesin, sulfonamides, triamterene, and the protease inhibitors indinavir and nelfinavir). 14. Study participants \<2 yrs life expectancy 15. Non-English Speakers 16. History of Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) 17. Anatomical urologic abnormalities including ileal conduits, horseshoe kidney, megaureter or solitary kidney. 18. Psychiatric conditions impairing compliance with the study 19. Vulnerable population (prisoner and/or cognitive impairment that the investigator feels will impact the study participant's ability to participate in the protocol) 20. Individual who will be unable to participate in the protocol in the judgment of the investigator.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Children's Hospital
Dallas, Texas, 75390, United States
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Children's Hospital of Philadelphia
Philadelphia, Pennsylvania, 19146, United States
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Cleveland Clinic
Cleveland, Ohio, 44195, United States
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Mayo Clinic
Rochester, Minnesota, 55905, United States
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University of Pennsylvania
Philadelphia, Pennsylvania, 19104, United States
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University of Texas Southwestern
Dallas, Texas, 75390, United States
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University of Washington
Seattle, Washington, 98195, United States
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Washington University, St. Louis
St Louis, Missouri, 63110, United States
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