The kidneys remove most of the uric acid in the body. When kidney function is reduced, uric acid builds up more easily and the risk of gout goes up. High uric acid can also cause kidney stones. If you have kidney disease, attacks and prevention need medicines that are safe for the kidneys, and you should usually avoid ibuprofen (Ibux).
By the Nyrami editorial teamPublished 9 October 20269 min read
Perhaps you woke up last night with a big toe so red, swollen and painful that even the duvet felt too heavy. Or perhaps you have kidney disease and have been told your uric acid is high. Gout and the kidneys are closely linked, and when you have both, there are a few extra things to keep in mind. Here is the overview.
Uric acid is a waste product made when the body breaks down purines, substances found in our cells and in food. The kidneys remove most of the uric acid. In about nine in ten people with gout, the main cause is that the kidneys remove too little. When kidney function weakens, uric acid therefore rises more easily, and gout becomes more common.
In a large American survey, gout was about twice as common in people with kidney function equal to stage 3 as in people with normal kidney function. Water tablets (diuretics), which many people with kidney disease and high blood pressure take, can also raise uric acid.
The link goes both ways. When a lot of uric acid passes into the urine, crystals can form and turn into kidney stones. Uric acid can also be deposited in the kidneys and urinary tract themselves. In studies, high uric acid is linked to faster worsening of kidney disease, but it has not been shown that uric acid lowering medicine slows kidney disease in people who do not have gout. That is why the international guideline KDIGO does not recommend such medicine just to protect the kidneys.
A gout attack causes a sudden, very painful joint that is swollen, warm and red. In more than half of attacks it is the big toe, but the ankle, knee, foot, hand and elbow can also be affected. The attack often starts at night, is worst after 12 to 24 hours and settles after a few days.
Without treatment, an attack can last a week or more. Some people get a fever. Between attacks most people have no symptoms at all, and there can be months or years between them. If uric acid has been high for a long time, lumps of uric acid crystals called tophi can form under the skin, for example on the ears, fingers or elbows.
Gout is the most common inflammatory joint disease after the age of 40. Around one to two per cent of adults in Western countries have it, most of them men. Among men over 75, about one in ten has had gout. After the menopause, women are affected almost as often as men.
The conditions that most often need to be told apart from gout are infection in the joint (septic arthritis), pseudogout and other forms of arthritis. Joint infection is serious and must be treated quickly. Think of it if you have a fever, feel unwell, or if the attack feels different from the ones you have had before.
Pseudogout looks similar, but is caused by calcium pyrophosphate crystals instead of uric acid. It more often affects the knee and older people. The surest way to tell them apart is to draw a little fluid from the joint and look for crystals under a microscope.
A blood test for uric acid is useful, but it can mislead you. In more than four in ten people, uric acid is normal during the attack itself, because the kidneys remove more uric acid then. The test is therefore often repeated two to four weeks after the attack. If uric acid is normal then too, the doctor should consider another explanation.
Yes, gout is counted as a rheumatic disease. It is joint inflammation caused by crystals, and it belongs to the specialty of rheumatology. Most people are still followed up by their GP (fastlege), and only some need to see a rheumatologist.
Gout, or podagra when it affects the big toe, is partly hereditary. Your genes affect how well the kidneys remove uric acid, and the disease often runs in families. Genes alone rarely decide, though. Overweight, alcohol, sugary drinks, water tablets, kidney disease, diabetes and high blood pressure matter a lot. In rare cases, inherited faults in how the body handles uric acid cause disease already in children and young people. Read more about genes and the kidneys in Is kidney disease hereditary?.
With kidney disease, KDIGO recommends low dose colchicine, or prednisolone as tablets or an injection into the joint, rather than anti-inflammatory painkillers such as ibuprofen (Ibux). Treatment works best when started early, ideally within a day. The attack then often settles within one to two days.
NSAIDs such as ibuprofen (Ibux), diclofenac (Voltaren) and naproxen are widely used for gout in people with healthy kidneys. With kidney disease they can weaken kidney function, and with an eGFR below 30 they should not be used. Read more in Painkillers and the kidneys.
Colchicine has to be adjusted to kidney function. With severely reduced kidney function, treatment should be agreed with a kidney specialist. Colchicine must not be used together with ciclosporin (Sandimmun), and people with a kidney transplant who take such medicines must always ask their kidney doctor first. Prednisolone is a good alternative when colchicine or NSAIDs do not suit you, but it is used as a short course. Ask your doctor for a plan for what to take next time an attack comes, so you can start quickly at home.
Gout medicines and what applies with kidney disease
Colchicine
Prednisolone
Ibuprofen, diclofenac, naproxen (Ibux, Voltaren)
Allopurinol (Allopur, Zyloric)
Febuxostat (Adenuric)
Probenecid
Allopurinol is the first choice for lowering uric acid and preventing new attacks, also with kidney disease. It is started at a low dose and stepped up carefully with regular blood tests, in smaller steps when kidney function is reduced. The target is usually a uric acid below 360 µmol/l, or below 300 µmol/l if you have tophi.
With kidney disease, KDIGO recommends considering uric acid lowering treatment already after the first attack. For the first six months, many also take colchicine or low dose prednisolone, because attacks can flare up when uric acid starts to fall. Do not stop allopurinol if you get an attack along the way, but talk to your doctor. If you get a skin rash, stop and contact a doctor.
Febuxostat is an alternative if allopurinol does not work well enough or causes side effects. It is broken down in the liver and needs less adjustment with reduced kidney function, but it is not used when eGFR is very low, and preferably not with heart disease. If you have a kidney transplant and take azathioprine (Imurel), allopurinol must not be used without your kidney doctor involved. You can read more about how your medicines work together in Medicines for kidney disease.
What matters most in your diet is drinking little alcohol, especially beer, and avoiding sugary drinks high in fructose. Also limit offal and purine rich seafood such as shellfish, herring, mackerel and anchovies. Diet alone rarely lowers uric acid enough to prevent new attacks, though, so it does not replace medicine.
Low fat dairy products, vegetables and fruit seem to protect against gout. With kidney disease you may still need to watch phosphorus and potassium, but only if your blood tests show they are too high. See Food with kidney failure and Phosphorus in food.
An apple is perfectly fine when you have gout. Fruit is part of the recommended diet, and a normal portion of fruit gives little fructose. It is drinks high in sugar, such as apple juice and large amounts of fizzy drinks, that are the problem. There is no good evidence that apples lower uric acid.
It is not well documented that cod liver oil (tran) or other omega 3 supplements prevent gout attacks, and Norwegian advice on gout does not mention it. Cod liver oil cannot replace medicine. If you have kidney disease, ask your doctor before starting any supplement.
Contact your GP (fastlege) the first time you get a painful, swollen and red joint, and if attacks come back. With kidney disease it is especially important that the doctor chooses the medicine, because several of the usual gout medicines need to be adjusted to the kidneys.
In the Nyrami app you gather your values, such as eGFR, creatinine and blood pressure, explained in words, and you can log how much you drink. The food scanner reads the barcode and assesses potassium, phosphorus, sodium and protein for you. It does not assess purines. The app is free for iPhone and Android.
Turns the advice into something you can use in the shop and the kitchen: scan food and see potassium, phosphorus and salt assessed for you, and follow your numbers over time. Free on iPhone and Android.
Acute kidney failure, which doctors now call acute kidney injury (AKI), means the kidneys stop working properly over hours or days. Common causes are fluid loss, serious infection and certain medicines. Many people recover fully or almost fully when the cause is treated quickly, but the risk of chronic kidney disease rises afterwards.
A simple cyst on the kidney is common and almost always harmless. Polycystic kidney disease (ADPKD) is something else: an inherited disease in which many cysts grow in both kidneys. Each child has a one in two chance of inheriting it. Good blood pressure control and sometimes the medicine tolvaptan can slow it down.
IgA nephropathy, also called IgA nephritis or Berger disease, is a chronic inflammation of the tiny filters in the kidneys. It most often affects young adults and typically causes blood in the urine a couple of days after a cold. The course varies a lot: many stay stable for decades, but some develop kidney failure. Treatment can slow it down.
