At the end of each surgery, I review the day’s blood test results one by one, linking every number back to the person behind it. Most are reassuring. Some call for a quick follow-up. And every so often, a result is urgent enough that the laboratory phones us before I have even logged on.
But there is one finding I see repeatedly — a sign of a condition many patients have never heard of, largely because it often develops silently and causes no obvious symptoms.
What worries me is how many people across the US may be living with the same disease without realizing it.
Linda, who I spoke with last week, is a typical example. She has high blood pressure and takes medication to control it, so she has routine blood tests every year.
One of those checks measures kidney function. When it was reviewed alongside a urine test, the results showed she had a condition known as chronic kidney disease.
Her immediate questions were simple and understandable: “What does that actually mean? And should I be worried?”
Chronic kidney disease, often shortened to CKD, affects nearly one in seven adults in the United States — about 37 million people. Each year, it contributes to at least 38,000 deaths, according to the CDC, a toll higher than the annual deaths linked to melanoma or to brain and prostate cancers.
Despite that, most people with chronic kidney disease are walking around completely unaware they have it.
That is because CKD does not behave like other serious diseases. Think of it less as a single illness and more as a risk factor.
The kidneys essentially clean the blood – removing waste and excess water to make urine. But for those with CKD, the kidneys slowly stop functioning properly, meaning they remove less waste and water.
If symptoms of the condition do appear, they tend to be vague at first – tiredness, most commonly, as well as brain fog and itchy skin
The kidneys essentially clean the blood – removing waste and excess water to make urine. But for those with CKD, the kidneys slowly stop functioning properly, meaning they remove less
Eventually, the kidneys can give out completely – known as kidney failure – meaning dialysis, blood cleaning treatment, or an organ transplant will be needed.
Thankfully, however, this is very rare, affecting less than two percent of patients.
Instead the real danger, even when the disease is mild, is the extra strain it puts on the heart and blood vessels.
People with CKD are around 20 times more likely to die of a heart attack or stroke than they are to ever reach kidney failure.
Like Linda, most people with CKD have no symptoms at all in the early stages, because the body compensates so well for a decline in kidney function.
That is exactly why most cases are only picked up by chance, when a blood or urine test is done for something else entirely.
If symptoms do appear, they tend to be vague at first – tiredness, most commonly, as well as brain fog and itchy skin.
Later on, you may notice weight loss, swollen ankles, feet or hands, breathlessness, blood in your urine, needing to urinate more often or muscle cramps.
By the time you notice any of this, the disease has often been present for years.
And, unlike many other diseases, there is no reversing CKD. It cannot be cured and the damage cannot be healed.
So what causes CKD?
CKD is closely tied to diabetes, high blood pressure – and the relationship runs both ways.
Diabetes and high blood pressure damage the kidneys, but damaged kidneys also increase blood sugar (the symptom of diabetes) and push blood pressure up.
Both conditions are typically triggered by poor lifestyle – namely an unhealthy diet, a lack of exercise and excessive drinking and smoking.
For most patients, the only way to get diagnosed is via two simple tests that a primary care physician can order.
One is a blood test that measures for creatinine, a waste product the kidneys should be clearing, and is used to calculate how well the organs are working.
The other is a urine test that looks for something called albumin, a protein that leaks into the urine when the kidneys are damaged.
Anyone with diabetes or high blood pressure should ask their doctor for these tests.
Early diagnosis of CKD is crucial because, while it cannot be reversed, it can be halted.
Getting blood pressure down and diabetes under control are crucial. This can be done by losing weight if you need to, eating a balanced diet – one that is rich in fruit, vegetables and whole grains – but low in salt and sugar.
Staying active matters enormously too. Exercise cuts your risk of heart disease, and CKD is fundamentally a heart problem in disguise.
If you smoke, quit, and keep your alcohol consumption low.
Previously, health officials said women should drink no more than one alcoholic beverage per day while men should drink no more than two – ideally much less.
However, alongside these lifestyle changes, there are also effective medicines.
A decade ago, there were few drugs that could help CKD patients.
But there has been a genuine breakthrough in recent years: a class of medicines called SGLT2 inhibitors – the most well-known called dapagliflozin and empagliflozin.
Originally developed for diabetes, they have been shown in major trials to significantly slow the decline in kidney function and cut the risk of heart failure and death in people with CKD whether or not they have diabetes.
Any CKD patient who hasn’t been offered one of these tablets should speak to their doctor about the possibility of taking them.
There are many more Lindas out there who don’t yet know they have this disease. If you’re aged 40 to 74 with no other health conditions, you’re entitled to an NHS health check every five years, covering blood pressure, blood glucose and cholesterol – and if your blood pressure is raised, your kidney function too.
Don’t leave it until it’s too late and you begin to show symptoms – or even have a heart attack. Get checked now.
