Its symptoms are elusive but there are ways to combat this silent killer. Read on for what you need to know
Dick de Jonge used to ride his bike to work daily, but in 2014, he noticed his cycling was getting slower.
“I thought there was something wrong with my bicycle,” says de Jonge, 69, of Groningen in the Netherlands. But he was the one slowing down: he didn’t know it, but he'd lost much of his kidney function.
One night he went to bed, exhausted, and slept for two days. Concerned, he saw his doctor. His blood-pressure was so high that he was sent to the hospital, where a urine test confirmed kidney problems. De Jonge had cancer in one kidney, and the other functioned at just seven per cent.
Though many people don’t realise they have it, kidney disease doesn't discriminate: it affects men and women of all ages and ethnicities. Last year, it became the tenth-ranked cause of death worldwide, according to the World Health Organisation, rising from 13th in 2019.
Says Dr Raymond Vanholder, president of the European Kidney Health Alliance in Brussels, one in ten people in Western Europe, and one in 13 people in Central and Eastern Europe, have some form of kidney disease. And according to some estimates, twice as many Europeans could have kidney disease in ten years’ time.
"According to some estimates, twice as many Europeans could have kidney disease in ten years’ time"
Why is it so prevalent? Because the two most common causes of the disease are hypertension—high blood pressure—and diabetes, and these have become more widespread (less-common causes include infections and genetic conditions; kidney stones can also raise risk for chronic kidney disease).
The cause for Dick de Jonge was likely high blood pressure. His cancerous kidney was removed, and he started dialysis. Dialysis does what kidneys should do: remove waste, salt, and extra water to prevent them from building up in the body; keep potassium and sodium at safe levels; and help control blood pressure.
Typically, dialysis is needed when kidney function is less than ten per cent. Depending on the type of dialysis, sessions last a few hours and are done three times a week.
About six months later, de Jonge’s kidney function improved to 25 per cent, where it still hovers, and he was able to stop dialysis. He takes medication for hypertension and sees his nephrologist every three months. “When they tell you that you have to get dialysis, it’s very scary,” he says. “Until that time, I was in control of my life. When I learned I had kidney disease, I wasn't in control anymore.”
Most people don’t know how important their two kidneys are to overall health. When they’re functioning properly, these organs filter waste and excess fluid out of the bloodstream, turning it into urine.
But excess sugar in your blood as a result of diabetes damages your kidneys’ filter over time. And uncontrolled high blood pressure can eventually cause arteries around the kidneys to narrow, weaken, or harden, making it difficult for them to deliver enough blood to kidney tissue.
“The kidney is extremely dependent on blood flow,” Dr Vanholder says. “Once the vessels or the heart get damaged, that has a negative impact on the kidneys. When they do not work, you get an accumulation of metabolites, and these damage the heart and the vessels.
So, you get this vicious circle.” People with kidney disease tend to die of complications from associated conditions, including heart disease, diabetes, stroke, and even cancer, before they die of kidney failure.
After age 50, the kidneys gradually become less efficient, and after 60, a moderate loss of function can be normal, as long as there are no other signs of kidney disease.
“Ten per cent of function is lost from the age of 50, every ten years,” Dr Vanholder says. Because moderate loss of kidney function is a normal part of ageing, experts actually recommend against screening everyone for kidney disease.
Instead they advise annual testing for those at increased risk: with diabetes, hypertension, or a family history of kidney disease. Though most often there are few or no symptoms, people of any age with fatigue, trouble sleeping, blood in the urine, or dry, itchy skin should get tested.
"Because moderate loss of kidney function is a normal part of ageing, experts actually recommend against screening everyone for kidney disease"
Depending on the severity, people may simply need to monitor their condition or limit salt in their diet. If medications are required, they include ACE inhibitors and ARBs, two classes of blood-pressure-lowering medication that slow down or prevent further kidney damage.
“Medication dramatically reduces the risk of dialysis and the worsening of kidney function,” says Dr Michel Jadou, who is co-chair of the Brussels-based organisation Kidney Disease: Improving Global Outcomes.
A newer drug class, SGLT2 inhibitors, are prescribed for diabetes and limit the body’s absorption of salt, which helps kidney function.
“Several clinical trials have been published that demonstrate how these drugs protect against heart failure and cardiovascular death, and slow down the progression of chronic kidney disease,” says Dr Juan Manuel Buades Fuster, chief of nephrology at Hospital Universitario Son Espases in Mallorca, Spain.
“They are probably the most important drugs in kidney protection in the last decade.” And sometimes, dialysis, or even a transplant, is necessary.
Claire Pullinger, United Kingdom
In 2017, Claire Pullinger believed that she was in perfect health. She’d been a vegan for years and stayed in shape by running. But after her dentist sent her for testing because her gums looked anemic, she got some surprising news: her kidneys were functioning at 50 per cent capacity, although she hadn’t experienced any problematic symptoms.
Soon after, she was diagnosed with silent polycystic kidney disease, a genetic condition in which cysts develop within the kidneys and can damage them to the point of failure.
“It came as a bit of a shock,” says Pullinger, 53, of Dorchester, England. For some people with early-stage kidney disease, lifestyle improvements may be enough to ward off other treatments.
Pullinger is one such patient: so far, she has maintained kidney function thanks to her diet and exercise habits. She avoids salt, coffee, alcohol, and sugar, and continues to exercise regularly. She maintains a healthy weight, and meditates to reduce stress levels.
Her kidney function has stabilised at around 35 per cent. “I try to be quite disciplined with my diet,” says Pullinger. “I think if you treat your body with that kind of respect, then you are rewarded.”
Daniel Gallego, Spain
In 1993, Daniel Gallego of Valencia, Spain, then age 20, sought medical attention for a swollen ankle, and was surprised to receive a diagnosis of kidney disease; it turns out he had been retaining fluid because his kidneys weren’t working well. Swelling in the lower leg extremities, with no pain, can be an early sign of kidney disease. The body can retain sodium when the kidneys don’t filter the blood as efficiently as normal.
For a long time, Gallego tried to manage his disease with diet and medication. He even had a transplant in 1998 that failed. In 2019, after several years of going to a dialysis centre three times a week, Gallego was able to switch to home dialysis. Now he performs dialysis on himself five times a week, on his own schedule.
When younger people are diagnosed with chronic kidney disease, doctors work quickly to help them preserve their health, since younger patients expect to have decades of life ahead. Says Dr Jadoul, they should do what they can to avoid health risks overall. Those things, he says, include keeping to a healthy weight, watching cholesterol and blood-pressure levels, exercising, and avoiding any kind of smoking.
Young adults who follow these lifestyle habits and their doctor’s advice tend to live longer. “Any percentage of kidney function that can be maintained for long periods of time will help people to live longer,” Dr Jadoul says. He says he has patients with serious kidney disease that manage it for decades.
Home dialysis isn’t always an option, but for those who can do it, it’s often an advantage. Says Daniel Gallego, who is now 48 and acts as president of the European Kidney Patients’ Federation, “I can do it during the morning, or if I have meetings, I can do it at night. It gives me a lot more freedom.”
Elizabeth MacKenzie, Canada
When Elizabeth MacKenzie, 69, of Vancouver was in her late forties, she was diagnosed with silent polycystic kidney disease (like Claire Pullinger) after frequently feeling exhausted and noticing blood in her urine, a possible symptom in people with kidney disease.
Fifteen years later, her kidney function dropped to 15 per cent, prompting her doctor to recommend transplantation.
MacKenzie was fortunate: her sister-in-law donated her kidney, so MacKenzie avoided going on a waiting list. “Many people wait for years,” she says. “Before the transplant I was feeling tired, but since then I have been leading an almost normal life. I’m sure it was a good thing to have the transplant before it was absolutely required. It likely meant a quicker recovery.”
Transplant recipients take immunosuppressant medication to prevent organ rejection, and their kidney function is lower than a healthy person’s. But they can live active lives. “Transplantation has a significant impact on quality of life,” Dr Buades Fuster says. “It is never the same as having healthy kidneys, but it is by far the best kidney replacement therapy at the moment.”
"Some experts believe that if more kidneys were available for transplantation, most people under age 60 could avoid dialysis"
Some experts believe that if more kidneys were available for transplantation, most people under age 60 could avoid dialysis. Many patients are placed on transplant waiting lists before beginning dialysis. For healthier candidates, it’s a temporary holding measure until an organ becomes available.
“There are not enough kidneys,” Dr Buades Fuster says. “Most patients under 60 will need dialysis before they get a kidney transplant.”
Reduce Your Risk
Fortunately, you can take steps to help lower your risk of kidney disease. Aside from controlling high blood pressure and avoiding diabetes, see your doctor regularly. Maintaining a healthy weight also helps, as more weight makes kidneys work harder. Over time, that extra work can cause kidney damage.
And it’s important for anyone, not just kidney patients, to avoid adding salt to food. Excess salt raises blood pressure and makes kidneys work harder. Consuming fewer than five grams of salt a day could could save 2.5 million lives annually.
Because most salt we consume is in prepackaged foods, World Health Organisation member states have agreed to help reduce their population’s salt intake by 30 per cent by 2025, and have instituted policies to reduce salt in packaged foods and restaurant meals. Two more things to be aware of: first, ask your doctor if you should avoid NSAID painkillers (non-steroidal anti-inflammatory drugs).
One recent study found that 41 per cent of people with kidney disease took NSAIDs, not realising the damage they could cause. “For those in high-risk groups, short-term use for heavy pain may be okay, but long-term use is not desirable,” says Dr Jadoul. Second, avoid smoking; it damages blood vessels and speeds up the deterioration of the kidneys. People who don’t smoke are more likely to preserve kidney function.
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