Welcome back to my prevention series, where I am taking what I consider to be the major health conditions and giving you my take on the medical evidence for reducing risk. This week I want to talk about two things that are often silent for many years, but have enormous consequences over time: high blood pressure and kidney disease. I have grouped these together because they are so closely linked. High blood pressure can damage the kidneys. Kidney disease can make blood pressure harder to control. Both increase the risk of heart attacks, strokes, heart failure, atrial fibrillation, vascular disease and premature death. Yet both can sit quietly in the background for years. That is the slightly uncomfortable part. So often I see patients in clinic who have felt completely well, exercise, work, travel, look after their family and have no symptoms at all, while their blood pressure is quietly too high, or their kidney function is slowly declining, or there is protein leaking into the urine. Often, symptoms only appear very late in the disease process. This is why I think these conditions deserve much more attention in any serious discussion about prevention.
There is nothing glamorous about blood pressure or kidney tests. They are not new, exciting or technologically impressive, but if I had to choose a small number of things that reliably matter for long-term health, they would be very near the top of the list.
Why blood pressure matters
Blood pressure is one of the best examples of a risk factor that people often underestimate because they cannot feel it. Very high blood pressure can sometimes cause symptoms, but most high blood pressure does not. It is usually found because someone checks it, or they have a routine check, for example with their GP. That creates a problem. If something does not hurt, and does not make us breathless, and does not obviously interfere with day-to-day life, it is easy to ignore. But blood vessels, the heart, the brain and the kidneys do not ignore it. They are exposed to it every minute of every day.
One of the ways I think about blood pressure is as a form of cumulative strain. A single mildly raised reading may not mean very much, especially if someone is stressed, rushing, in pain or sitting in a clinic, but persistently raised blood pressure over years is different. It changes the workload on the heart. It damages blood vessels. It contributes to stiffening of the arteries. It increases the risk of stroke. It increases the risk of kidney disease. It is one of the major drivers of heart failure and atrial fibrillation.
In cardiology, this is a pattern I see all the time. Someone may present in later life with atrial fibrillation, breathlessness, a thickened heart muscle, heart failure with preserved ejection fraction, kidney impairment or vascular disease. Often, when you look back, blood pressure has been part of the story for many years. In fact, in my weekly heart failure clinic, this is the single commonest risk factor I see. I would go further and say it is often not patients with incredibly high blood pressure, but those with modestly elevated blood pressure for far too long. I think that often surprises people.
That does not mean blood pressure is the only cause. It rarely is. Age, weight, genetics, salt intake, sleep, alcohol, diabetes, kidney disease, stress, medication and many other things may all contribute. But blood pressure is one of the things we can measure and often improve, which is what makes it such an important prevention target.
Why kidney disease matters
Kidney disease is another condition that can be silent for a long time. The kidneys are often thought of simply as filters, but they are much more than that. They help regulate fluid balance, blood pressure, electrolytes, acid-base balance, hormones, bone health and red blood cell production. They are also deeply connected to cardiovascular health, and in fact many heart multidisciplinary meetings would be enhanced by having a kidney specialist involved.
From a prevention point of view, one of the most important messages is that kidney disease is not only about the risk of dialysis. Dialysis matters, of course, and advanced kidney failure is life-changing. But many people with chronic kidney disease will never need dialysis. The bigger risk for many is cardiovascular disease. This is why kidney markers should be taken seriously even when someone feels completely well. In routine practice, kidney health is often assessed using blood tests, particularly something called creatinine and estimated glomerular filtration rate, or eGFR. These are useful, but they are not the whole story. A urine test looking for albumin, often measured as an albumin-to-creatinine ratio, or ACR, can be just as important. This is because protein leaking into the urine can be an early sign of kidney damage and a marker of blood vessel vulnerability. Someone can have a reasonably preserved eGFR but still have an abnormal urine ACR, and that can change their risk profile.
This is one of the things that I think is sometimes missed in general health screening. People may have had “normal kidney function” on blood tests, but no urine ACR checked. That may be fine in a genuinely low-risk person, but in those with high blood pressure, diabetes, cardiovascular disease or other risk factors, urine testing can add important information.
Blood pressure and kidneys: a two-way relationship
Blood pressure and kidney disease are tightly linked. High blood pressure can damage the small blood vessels in the kidneys, gradually reducing kidney function and increasing protein leakage. Kidney disease can then make blood pressure harder to control, partly because of salt and fluid handling, hormonal changes and vascular stiffness. It can become a vicious cycle. This is one reason why kidney disease is so important in cardiovascular prevention. It is not a separate issue sitting quietly in the background. It is part of the same system. The heart, kidneys, blood vessels and metabolism are connected. Diabetes, obesity, high blood pressure, kidney disease and heart disease often cluster together. This is why modern prevention increasingly needs to be joined up rather than divided into separate organ systems. Someone may think they are having a “heart health check,” but if we ignore kidney function, urine ACR, blood pressure and metabolic risk, we are missing part of the picture.
What we cannot control
As always in this series, it is important to start with what we cannot control. We cannot change our age. Blood pressure and kidney disease both become more common with age. We cannot change the genes we were born with. Some people have a strong family tendency to high blood pressure or kidney disease. Some people develop kidney disease because of autoimmune conditions, inherited kidney disorders, previous kidney inflammation, urinary tract problems, pregnancy-related complications, severe infections, cancer treatments, or other medical conditions that were not their fault. Some people also have a history of acute kidney injury during severe illness or hospital admission, which can increase later risk. As ever, this is not about blame. Many people with high blood pressure or kidney disease have done nothing wrong, but it is also not true that nothing can be done. These are exactly the sorts of conditions where prevention, measurement and early treatment can make a real difference.
What we can influence
The first thing we can influence is whether we know our numbers. For blood pressure, that means measuring it properly. A single clinic reading is not always enough. Blood pressure varies during the day and is affected by stress, pain, caffeine, exercise, sleep, alcohol, anxiety and even the act of being in a medical setting — often called white-coat hypertension, although I have not worn a white coat at work since 2002! This is why home blood pressure monitoring or ambulatory blood pressure monitoring can be so useful. It gives a better sense of what blood pressure is doing in real life.
I often find that people fall into one of two traps. Some panic about an isolated high reading. Others dismiss repeated high readings because they feel well. Neither is ideal. The aim is to understand the pattern. If blood pressure is persistently high, it deserves attention.
Lifestyle measures can make a meaningful difference. Weight loss, regular exercise, reducing salt intake, moderating alcohol, improving sleep, treating sleep apnoea where present, stopping smoking and improving metabolic health can all help. Resistance training and aerobic exercise both matter, although if blood pressure is very high, it should be assessed before starting vigorous exercise.
Diet matters too. For some people, salt intake is a major driver. This does not mean everyone needs an extreme diet, but many processed foods contain far more salt than people realise. A diet built around mostly whole foods, vegetables, fruit, legumes, nuts, whole grains, fish, lean protein and sensible portions will generally support both blood pressure and kidney health.
Medication also matters. There is sometimes a reluctance to take blood pressure tablets because people feel it represents failure. I do not see it that way. If someone’s blood pressure remains high despite sensible lifestyle measures, medication can be one of the most effective prevention tools we have. The goal is not to “medicalise” life. The goal is to reduce long-term strain on the brain, heart, kidneys and blood vessels.
For kidney health, the key is not just measuring creatinine once and forgetting about it. It is about looking at risk in context. For many people, the practical steps are straightforward: control blood pressure, manage diabetes well, reduce salt, avoid smoking, avoid unnecessary kidney-stressing medication, treat cholesterol appropriately, and monitor kidney function and urine ACR at sensible intervals. For some patients, modern drug treatments have also changed the landscape. SGLT2 inhibitors, originally developed for diabetes, are now used in selected patients for kidney and heart protection. ACE inhibitors or angiotensin receptor blockers can be particularly helpful in people with high blood pressure and albuminuria. Other treatments may be appropriate depending on diabetes, protein leakage, heart failure and overall risk.
The details need individual medical advice. But the broader point is simple: kidney risk is no longer something we should passively observe until it becomes advanced. There are now meaningful ways to reduce risk and slow progression in the right patients.
Screening and early detection: why it is complicated
Screening for blood pressure is both simple and complicated. It is simple because measuring blood pressure is easy. It is cheap, quick and widely available. It is complicated because blood pressure is variable, and because treatment decisions should be based on a reliable pattern, not one number taken in a stressful moment. This is why I like home blood pressure monitoring when it is done properly. The technique matters: sitting quietly, using the right cuff size, resting beforehand, arm supported, taking repeat readings, and recording results rather than relying on memory.
For kidney disease, screening is also relatively simple in principle. A blood test and urine test can tell us a lot. But interpretation requires context. A mildly reduced eGFR in an older person may be stable and low risk. The same eGFR in a younger person may be more concerning. A normal eGFR with a high urine ACR may be more important than people realise. A borderline result may need repeating rather than immediate alarm. A trend over time is often more useful than a single value.
This is why prevention is not just about ordering tests. It is about interpreting them properly and acting on them in a proportionate way. One of the mistakes in modern healthcare is that we sometimes jump to advanced scans and complex tests while missing the basics. I am very interested in advanced diagnostics when they are useful, but the foundations still matter enormously. Blood pressure, kidney function and urine ACR are part of those foundations.
Key takeaways
High blood pressure is usually silent, but it can cause major long-term damage.
Blood pressure affects the brain, heart, kidneys and blood vessels.
Kidney disease can also be silent for many years.
Kidney risk is not just about eGFR; urine ACR can be very important.
Blood pressure and kidney disease often drive each other.
The biggest risk for many people with chronic kidney disease is cardiovascular disease, not only dialysis.
Lifestyle measures matter: exercise, weight, salt, alcohol, sleep, smoking and metabolic health all play a role.
Medication for high blood pressure is not failure. Used well, it can be powerful prevention.
The aim is not to chase perfect numbers. The aim is to reduce long-term risk and preserve health.
For those who want to go deeper
One of the themes I keep returning to in this series is that prevention should not be fragmented. Blood pressure is not just a “GP issue.” Kidney disease is not just a “renal issue.” Cholesterol is not just a “cardiology issue.” Diabetes is not just an “endocrine issue.” Frailty is not just an “older person’s issue.” These things interact. A person with high blood pressure, early kidney changes, raised blood sugar, excess visceral fat, poor sleep and a family history of heart disease does not need five separate conversations that never connect. They need someone to look at the whole pattern and ask: what is the trajectory, what is modifiable, and what should we prioritise? That is why I think long-term prevention needs to become more integrated. It should include proper measurement, sensible interpretation, personalised targets, lifestyle support, medication where appropriate, and follow-up over time. Not just a one-off set of numbers, but an understanding of direction.
A plan that looks perfect on paper but does not fit someone’s life is not a good prevention plan. The best plan is one that is medically sound and actually doable. High blood pressure and kidney disease are not dramatic in the early stages. They do not usually announce themselves. They do not necessarily stop someone working, travelling, exercising or enjoying life, which is exactly why they matter. Prevention is often about paying attention before symptoms appear. It is about not waiting for the stroke, the heart failure admission, the atrial fibrillation, the kidney decline or the vascular event before taking risk seriously. We cannot control everything. We cannot remove all risk. But we can measure the things that matter, understand them properly, and act early where action is likely to help. Blood pressure and kidney health may not be glamorous. But if we care about staying well for longer, they are absolutely central.
This week’s video
In this week’s video, I actually veer slightly off topic. This morning — the eve of the England vs Mexico World Cup game — my son was asking me about the heart at altitude and how it might affect the players. I thought that could be a good topic for a short video. I’m sure watching the game itself won’t be good for anyone’s blood pressure though!
Come on England!