The Study Everyone's Talking About
"Drink more water."
If you've had a kidney stone, you've heard it. From your urologist, your ER doctor, your mom, the guy at work who had one in 2019. It's the universal prescription. The one piece of advice that every single stone patient walks out of the hospital with.
And look — it's not bad advice. Staying hydrated is important. Nobody is arguing otherwise.
But a massive new study just complicated the picture in a way that matters for anyone trying to prevent their next stone. Published this month in The Lancet — one of the most prestigious medical journals in the world — the PUSH trial is the largest randomized clinical trial ever conducted on hydration and kidney stone prevention. And its results are not what anyone expected.
What the PUSH Trial Actually Found
The Prevention of Urinary Stones with Hydration (PUSH) trial enrolled 1,658 kidney stone patients across six US academic medical centers. Two-thirds of participants were recurrent stone formers — people who'd already been through this more than once. The median age was 44, and 57% were female.
Participants were randomly assigned to one of two groups:
- Intervention group: A multi-pronged behavioral program designed to increase fluid intake. This wasn't just a pamphlet. Participants received a personalized fluid prescription, health coaching sessions, text message reminders, and financial incentives for meeting hydration targets.
- Control group: Standard guideline-based care — essentially the usual "drink more water" advice you get at your follow-up appointment.
The trial ran for two years, tracking symptomatic stone recurrence as the primary outcome.
The results
- 19% of the intervention group had a stone recurrence
- 20% of the control group had a stone recurrence
- Hazard ratio: 0.96 (95% confidence interval: 0.77-1.20)
That's a difference of one percentage point. Statistically, it's nothing. The coaching, the texts, the financial incentives, the personalized prescriptions — none of it moved the needle on stone recurrence.
The intervention did modestly increase urine volume. But "modestly" is the key word. It wasn't enough to change outcomes. And here's a detail that might surprise you: the intervention group actually reported more urinary symptoms — increased frequency and urgency — at 6 and 12 months. They were drinking more, feeling the effects of drinking more, and still getting stones at the same rate.
What This Does NOT Mean
This is where nuance matters, and where headlines will get it wrong. So let me be direct about what this study does not prove.
It does not prove that hydration doesn't matter. That would be a dangerous misreading.
What it proves is something more specific and, honestly, more useful: telling people to drink more water — even with coaching, money, and technology backing it up — doesn't reliably change behavior enough to prevent stones.
Several urologists have made this point clearly. Dr. David Canes, a urologist, noted on social media: "It really means that if you tell people to push fluids, and they don't drink the recommended amount, nothing changes. Says nothing about proper fluid intake and stones." Dr. Andrew Gabrielson, a urologic surgeon, added: "The intervention didn't increase urine volume production to the extent it may impact stone recurrence. Nonetheless the trial highlights challenges with achieving the 2.5L goal."
In other words: the intervention didn't fail because water is useless. It failed because getting people to actually drink enough water is really, really hard — and even a well-designed program with financial incentives couldn't overcome that.
The problem isn't that water doesn't help. The problem is that "drink more water" as a standalone strategy isn't actionable enough to change outcomes.
This is something most stone patients already sense intuitively. You leave the doctor's office with "drink more water" ringing in your ears, you buy a big water bottle, you do well for two weeks, and then life happens. The PUSH trial just confirmed that pattern at scale, with data, in The Lancet.
What Actually Works for Prevention
If the largest hydration trial ever conducted found that pushing fluids alone isn't enough, what is enough? The evidence points to a combination approach — multiple strategies working together, not a single silver bullet.
1. Diet matters as much as hydration
Roughly 80% of kidney stones are calcium oxalate. That means what you eat directly determines what ends up in your urine. You can drink three liters of water a day, but if you're eating a spinach salad with almond butter and washing it down with black tea, you're flooding your kidneys with oxalate faster than you can dilute it.
Hydration is dilution therapy. But dilution only works if you're also controlling what needs to be diluted.
2. Tracking beats willpower
The PUSH trial used coaching, text reminders, and financial incentives — and still couldn't change behavior reliably. That should tell us something important about how behavior change actually works.
Generic advice ("drink more") doesn't create awareness. Daily tracking does. When you log what you eat and drink, you start seeing patterns. You notice that your high-oxalate days cluster around certain meals, that your hydration drops on busy workdays, that your risk profile shifts when you travel. That awareness is what generic advice can never provide, no matter how many text reminders it comes with.
3. Know YOUR numbers
A 24-hour urine test tells you exactly what's driving your stone risk. For some people, it's low urine volume. For others, it's high urinary oxalate, low citrate, high sodium, or elevated uric acid. The PUSH trial treated all stone formers the same — push fluids. But stone formers aren't all the same. Your specific metabolic profile should drive your specific prevention plan.
If you've had a stone and haven't done a 24-hour urine collection, ask your urologist about it. It's the single most informative test for understanding your risk.
4. The combination approach works
No single intervention is enough. The evidence supports a multi-pronged strategy:
- Adequate hydration — target 2.5L+ of urine output daily (still important, even after this study)
- Dietary oxalate awareness — know which foods are high and manage your daily intake
- Calcium with meals — dietary calcium binds oxalate in the gut before it reaches your kidneys
- Adequate citrate — from citrus fruits or supplements if needed, to inhibit crystal formation
- Sodium reduction — high sodium intake increases urinary calcium excretion
The PUSH trial tested one pillar in isolation. Prevention works when all the pillars stand together.
If you've had kidney stones and your doctor's only advice was "drink more water," this study validates what many patients feel — that it's not enough. Ask about a 24-hour urine test, dietary oxalate assessment, and a full metabolic evaluation.
What We're Doing at OxalateGuard
We've never positioned hydration tracking as a standalone solution — and this study reinforces why. From day one, OxalateGuard has been built around the idea that prevention requires understanding what you eat, not just how much you drink.
Our food database tracks oxalate levels across 2,500+ foods. Our Menu Check feature helps you evaluate restaurant dishes before you order. And yes, daily logging helps you track hydration too — but alongside the dietary factors that the PUSH trial's "drink more water" approach completely ignored.
The data supports a comprehensive approach. That's exactly what we built.
The Bottom Line
Hydration matters. Let's be unequivocal about that. Adequate fluid intake remains an important part of kidney stone prevention, and nothing in this study changes that fundamental truth.
But "drink more water" — as a standalone prescription, even when backed by coaching, text reminders, and financial incentives — is not enough to prevent stone recurrence. The PUSH trial makes that clear with the strongest evidence we've ever had.
For the medical community, this should be a wake-up call. Patients deserve more than a water bottle and a pamphlet. They deserve comprehensive metabolic evaluation, dietary guidance that includes oxalate management, and tools that help them understand their individual risk profile.
For stone patients, the takeaway is both validating and empowering. If you've felt like "drink more water" wasn't enough — you were right. Prevention is a multi-factor problem that requires a multi-factor solution. Water is part of it. But only part.
This article is for informational purposes only and does not constitute medical advice. Always consult your physician or urologist for personalized kidney stone prevention guidance.
References
- Scales CD Jr, et al. Prevention of urinary stones with hydration (PUSH): a randomised clinical trial. The Lancet. 2026. DOI: 10.1016/S0140-6736(25)02637-6
- ClinicalTrials.gov Identifier: NCT03244189