Gout and Kidney Stones: The Link, Symptoms, Prevention, and Treatment

Gout and Kidney Stones: The Link, Symptoms, Prevention, and Treatment

TL;DR

• People with gout are about twice as likely to develop kidney stones. Acidic urine and high uric acid drive both problems.
• Hydration (aim for 2-2.5L urine/day), urine alkalinisation (potassium citrate), and lowering serum urate prevent stones.
• Test smart: serum urate, urine pH, stone analysis, and a 24‑hour urine study if stones repeat. Non‑contrast CT confirms diagnosis.
• Allopurinol or febuxostat lowers urate; potassium citrate dissolves uric acid stones by raising urine pH to 6.0-6.5.
• Urgent care if fever with stone pain, uncontrolled pain, vomiting/dehydration, or you have one kidney or are pregnant.

Why gout and kidney stones travel together

Here’s the simple version: the same chemistry that fuels gout can build crystals in your kidneys. High uric acid in the blood (hyperuricaemia) and low urine pH (acidic urine) push uric acid out of solution and into crystals. In joints, those crystals spark gout flares. In the urinary tract, they become stones.

How common is the overlap? Large cohort studies in the UK and US show people with gout have about a 2x higher risk of kidney stones, especially uric acid stones. Uric acid stones make up roughly 8-10% of all stones, but the share is higher in folks with metabolic syndrome, type 2 diabetes, and gout. It’s one of those times when biology takes the shortest path: acid + urate = rocks.

Why does urine get acidic? Insulin resistance lowers kidney ammonia production, which makes urine more acidic. That’s why people with central weight gain, high blood pressure, and prediabetes often show a low urine pH. If the urine stays acidic (think pH under ~5.5-6.0), uric acid struggles to dissolve and starts to crystallise.

There’s another quirk: high uric acid in urine can also help calcium oxalate stones form, because uric acid crystals can act as a scaffold for calcium oxalate to stick to. So, even if your stone isn’t pure uric acid, the gout chemistry may still be involved.

Guidelines have kept up with this. NICE’s 2022 guidance on gout recommends lowering serum urate below 360 µmol/L (6 mg/dL)-below 300 µmol/L (5 mg/dL) if you have tophi or frequent flares. The American College of Rheumatology (2020) says the same. On the stone side, European Association of Urology guidance (2025) stresses urine alkalinisation for uric acid stones and high fluid intake for all stone formers.

If you want one core idea to remember, it’s this: keep urate down and urine less acidic. That single strategy protects joints and kidneys.

So yes, gout and kidney stones are linked by the same chemistry. That’s the bad news. The good news: unlike bad luck, chemistry is fixable.

Spot the signs, tests, and when to act

Kidney stones rarely keep quiet. The classic story is sudden, severe pain in the side or back that waves in and out, often radiating to the groin. Nausea, vomiting, and seeing blood in the urine are common. You may feel a burning urge to pass urine but only manage a few drops.

When to seek urgent care (A&E in the UK):

• Fever or chills with stone pain (risk of a blocked, infected kidney)
• Uncontrolled pain or vomiting despite pain relief at home
• Unable to pass urine, or only one working kidney
• Pregnant, elderly, or immunocompromised

Red flags aside, how do you actually confirm a stone and figure out its type?

• Imaging: Non‑contrast CT is the gold standard for diagnosis and size/location. Ultrasound is used first in pregnancy and can help track hydronephrosis.
• Stone analysis: If you pass one, try to catch it using a fine strainer and send it for lab analysis. This tells you if it’s uric acid, calcium oxalate, or mixed-which changes prevention.
• Blood tests: Serum urate, kidney function (creatinine/eGFR), bicarbonate, calcium. If gout is active, urate can temporarily dip during a flare, so recheck after.
• Urine tests: Urine pH (spot or, better, home monitoring), and a 24‑hour urine collection if stones recur. You’ll get volume, uric acid, citrate, calcium, sodium, and oxalate. This pinpoints what to fix.

Targets that matter:

• Serum urate: below 360 µmol/L (6 mg/dL), below 300 µmol/L (5 mg/dL) if severe gout
• Urine pH (uric acid stones): 6.0-6.5. Much above 7.0 risks calcium phosphate stones
• Urine volume: at least 2.0-2.5 litres/day

Quick tip: get a cheap urine pH dipstick pack and check morning and evening for a week. If your numbers sit under ~5.5-6.0, you have a clear fix to make.

Prevention that actually works (food, fluids, meds)

Preventing stones when you have gout is not guesswork. There are a few levers, and they’re measurable. Use these levers daily and you lower the odds of both a gout flare and a 3 a.m. stone crisis.

1) Hydration with a number, not a hope

• Aim for 2-2.5 litres of urine per day. That usually takes 2.5-3.0 litres of fluids, more if you sweat or work outdoors.
• Keep water your default. Coffee and tea count toward fluids, but go easy on sugar and heavy cream.
• Colour check: pale straw urine is your simple, free dashboard.

2) Make urine less acidic (this dissolves uric acid stones)

• Potassium citrate is the go‑to. It raises urine pH and adds citrate, a natural anti‑crystal compound. Target urine pH 6.0-6.5.
• Alternative if you can’t take potassium: sodium bicarbonate can work, but it may raise blood pressure or fluid retention. Discuss if you have hypertension or heart issues.
• Food angle: more vegetables and fruit (especially citrus), fewer refined carbs. That eating pattern nudges urine pH higher.

3) Lower serum urate to gout targets

• Allopurinol is first‑line in the UK. Dose is titrated (often starting 100 mg daily) to hit the urate target. Kidney function guides dosing.
• Febuxostat is an alternative if allopurinol isn’t tolerated. Earlier safety signals around heart risk have been debated; a large European trial found no extra risk compared with allopurinol when used appropriately. Your clinician will weigh your cardiovascular history.
• Probenecid increases uric acid excretion and can worsen uric acid stone risk. It’s generally avoided if you have a history of stones.
• Don’t stop urate‑lowering therapy during a stone or a gout flare. Keep going, and use flare prophylaxis (low‑dose colchicine, or an NSAID if appropriate) in the first months of therapy.

4) Food patterns that bend the chemistry your way

• Keep purines moderate: trim red meat and organ meats; go easy on anchovies and sardines. Choose poultry, eggs, tofu, and low‑fat dairy.
• Cherries and vitamin C in food have modest benefits for gout flares. High‑dose vitamin C supplements can raise urinary oxalate, so don’t megadose.
• Cut back on fructose‑sweetened drinks. Fructose spikes uric acid production.
• Salt down; calcium steady: less sodium (<2g/day sodium, about 5g salt) and a normal intake of calcium (1000-1200 mg/day from food) lower several stone risks.
• Lose weight gently if you need to. Fast crash diets raise uric acid and can trigger flares.

5) Medications that help-or hurt-stone and gout risk

6) A simple weekly checklist

• Fluids: Did I drink enough to keep urine pale and reach ~2-2.5L output?
• Food: At least five servings of veg/fruit; red/processed meat no more than a few times per week; no sugary drinks.
• Urate: Am I taking allopurinol/febuxostat daily? Any missed doses?
• Urine pH: Two spot checks this week; mostly 6.0-6.5?
• Salt: Stayed near UK target (about 5g salt/day)?
• Weight: Steady, not yo‑yoing.

7) Home decision cues

• If urine pH is low (<5.5) despite diet changes, ask your clinician about potassium citrate.
• If gout is controlled (urate at target) but stones recur, you likely need a 24‑hour urine to find the missing piece (often low citrate or high sodium).
• If you’re on a thiazide for blood pressure and getting more gout flares, don’t stop it on your own-ask about adding or adjusting urate‑lowering therapy.

Quick answers and next steps

FAQ

• Can uric acid stones be dissolved? Yes. Raise urine pH to ~6.0-6.5 with potassium citrate, drink enough, and keep urate down. Pure uric acid stones can shrink or disappear on this plan.
• My stone was “calcium oxalate.” Does gout still matter? It can. High uric acid in urine can promote calcium oxalate crystals. Lowering serum urate and improving urine chemistry still helps.
• Is beer worse than spirits for gout and stones? Beer is more gout‑triggering due to purines from brewer’s yeast. Spirits have less purine but still worsen urate via alcohol metabolism. If you drink, keep it modest and hydrate.
• Do I stop allopurinol during a gout flare or stone? No. Keep taking it. Manage flares with colchicine, NSAIDs, or steroids as appropriate. Stopping and starting makes flares more likely.
• What urine pH is too high? If you’re regularly over ~7.0, you may raise calcium phosphate stone risk. Tweak your citrate dose to hover around 6.0-6.5.
• Is vitamin C good or bad? Food is fine. High‑dose supplements can raise urinary oxalate. Don’t megadose if you’re a stone former.
• Do SGLT2 inhibitors help gout? They modestly lower serum urate and, in real‑world data, reduce gout and possibly stone events in people with type 2 diabetes. They are prescribed for glucose/renal/heart benefits first.
• What about baking soda for urine pH? It works but adds sodium. If you have high blood pressure or fluid retention, potassium citrate is usually preferred. Get advice before DIY.

Next steps: what to do based on your situation

• If you’ve had your first stone and you have gout: ask for stone analysis, a serum urate check, and urine pH testing. If the stone is uric acid or your urine pH runs low, discuss potassium citrate plus a plan to titrate allopurinol or febuxostat to target.
• If you’ve had multiple stones: request a 24‑hour urine profile. It’s the most efficient way to find the exact lever to pull (volume, sodium, citrate, uric acid, calcium, oxalate).
• If your blood pressure drug is a thiazide and gout flares rose: don’t stop it suddenly; bring it up with your GP. Options include adding urate‑lowering therapy or considering alternatives based on your health history.
• If you keep missing pills: set a daily reminder and link dosing to an existing habit (after brushing teeth). Uric acid climbs fast when you stop and falls slowly when you restart.
• If you’re unsure about urine pH: buy a small pack of pH strips and check morning/evening for a week. Bring the numbers to your appointment.

When to see your GP vs A&E (UK‑specific):

• See your GP: new stone symptoms without fever, or to discuss prevention after a stone. Bring your medication list. Ask about a 24‑hour urine if stones repeat.
• Go to A&E: fever/rigors with stone pain, uncontrolled pain or vomiting, inability to pass urine, known single kidney, or pregnancy with severe pain.

What the evidence says (for confidence, not homework):

• NICE (2022) sets clear urate targets and supports early urate‑lowering therapy in gout.
• ACR (2020) backs treat‑to‑target urate and continued therapy during flares.
• EAU Urolithiasis guidance (2025) recommends urine alkalinisation for uric acid stones and high fluid intake for all stone formers.
• Large observational cohorts (UK and US, 2010-2024) show ~2x higher stone risk in people with gout and higher uric acid stone rates.

A quick, practical plan to print or save

1. Hydrate: set a 2.5-3.0L/day fluid goal; check urine colour.
2. Urate: confirm your target (<360 µmol/L; <300 if severe) and titrate therapy to get there.
3. Urine pH: aim 6.0-6.5; use potassium citrate if diet alone doesn’t budge it.
4. Food: more plants and low‑fat dairy; less red/processed meat and sugary drinks; salt under 5g/day; keep calcium normal.
5. Follow‑up: repeat serum urate in 4-6 weeks after any dose change; consider a 24‑hour urine after recurrent stones.

Common pitfalls to avoid

• Stopping allopurinol during a flare or when you feel well. That yo‑yo triggers more flares and keeps stone risk high.
• Chasing water without measuring urine. Volume matters more than guesswork.
• Over‑alkalinising urine past pH 7.0. That trades one stone type for another.
• Cutting dietary calcium too low. That can raise oxalate absorption and backfire.
• Assuming all stones are the same. Stone analysis changes the playbook.

You don’t need to fix everything at once. Start with hydration and a urate target. Add urine pH work if your stone was uric acid or your pH sits low. Layer in food and salt habits you can actually stick to. That’s the stack that protects both your joints and your kidneys.

About Author

Sandra Hayes

Aug, 25 2025

I am a pharmaceutical expert who delves deep into the world of medication and its impact on our lives. My passion lies in understanding diseases and exploring how supplements can play a role in our health journey. Writing allows me to share my insights and discoveries with those looking to make informed decisions about their well-being.

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