Why Medicine Is Rethinking Heart, Kidney and Metabolic Health

Medicine has traditionally divided the body into departments. Heart problems go to cardiology. Kidney problems go to nephrology. Diabetes and other metabolic conditions go to endocrinology.

Biologically, the divisions are much less tidy. Obesity and dysfunctional body fat can affect insulin sensitivity and blood pressure. Diabetes can damage blood vessels and kidneys. Declining kidney function can substantially increase cardiovascular risk. Heart disease, kidney disease and metabolic dysfunction frequently develop together and can accelerate one another.

In 2023, the American Heart Association gave that interconnected problem a name: cardiovascular-kidney-metabolic syndrome, or CKM syndrome.

This year, the idea moved another step towards mainstream medicine. The first comprehensive clinical guideline for CKM syndrome was published in June 2026, recommending that clinicians assess and stage cardiovascular, kidney and metabolic health together rather than treating them as entirely separate problems.

Then, in August, researchers applied the framework to more than 1,200 Americans with an average age of just 23. Nearly 80% were already at CKM Stage 1 or above.

That figure sounds alarming. What it actually means is considerably more interesting.

TL;DR

• CKM stands for cardiovascular-kidney-metabolic syndrome. The American Heart Association introduced the framework in 2023 to recognise the interconnected relationship between metabolic health, kidney disease and cardiovascular disease.
• It isn't one disease with one test or treatment. CKM is an umbrella clinical framework describing a spectrum from optimal cardiovascular-kidney-metabolic health to established cardiovascular disease.
• There are five stages, from 0 to 4. Stage 0 means no CKM risk factors; Stage 1 involves excess or dysfunctional adiposity; Stage 2 adds metabolic risk factors or chronic kidney disease; Stage 3 represents high-risk CKM; and Stage 4 means established cardiovascular disease.
• CKM became considerably more important in 2026. The AHA, American College of Cardiology, American Diabetes Association and American Society of Nephrology issued the first comprehensive clinical guideline for preventing, detecting and managing it.
• The emphasis is increasingly on earlier identification. The new guideline recommends CKM staging across the life course and routine assessment of metabolic risk factors and kidney function.
• A new study of 1,283 young US adults found 79.3% at Stage 1 or higher. But this was one deliberately diverse cohort enriched for disadvantaged backgrounds, not a nationally representative estimate of everyone in their twenties.
• Most weren't at an advanced stage. 40.2% were Stage 1, 36.2% Stage 2 and only 2.8% Stage 3. None had Stage 4 disease.
• The more interesting finding was underneath the headline number. More advanced CKM stages were associated with measurable signs of early arterial injury at an average age of just 23.

Why Does CKM Syndrome Exist?

For decades, medicine has known that obesity, diabetes, chronic kidney disease and cardiovascular disease are connected. CKM attempts to formalise that connection.

The AHA defines the syndrome as a systemic disorder involving interactions between metabolic risk factors, chronic kidney disease and the cardiovascular system that can lead to multi-organ dysfunction and increased cardiovascular risk.

One pathway illustrates the problem. Excess or dysfunctional adipose tissue — particularly visceral fat around the abdominal organs — can promote inflammation, oxidative stress and insulin resistance. Insulin resistance can progress towards abnormal blood glucose and type 2 diabetes. High blood pressure, diabetes and other metabolic abnormalities can damage the kidneys. Kidney dysfunction can then increase cardiovascular risk through several mechanisms, while cardiovascular dysfunction can itself worsen kidney health.

Rather than a straight line from one condition to another, it's a network. That's the conceptual shift behind CKM. A patient doesn't necessarily have an isolated weight problem, then an unrelated blood-pressure problem, then an unrelated kidney problem and finally heart disease. Those findings may be different manifestations of the same interconnected process.

The Five CKM Stages

The framework divides that process into five stages. Understanding them is important because "having CKM syndrome" can mean very different things depending on the stage.

Stage 0 — No CKM risk factors. This is optimal CKM health. There is no excess or dysfunctional adiposity, no relevant metabolic risk factors, no chronic kidney disease and no cardiovascular disease. The goal here is essentially preservation: preventing CKM risk factors from developing.

Stage 1 — Excess or dysfunctional adiposity. Stage 1 is the earliest identifiable CKM stage. It includes excess body fat or dysfunctional fat distribution, particularly abdominal or visceral adiposity, before the metabolic or kidney abnormalities characteristic of later stages have developed.

The distinction between weight and fat distribution matters. BMI can identify overweight and obesity but doesn't reveal where fat is stored. The 2026 guideline therefore recommends assessing both BMI and waist circumference when characterising risk associated with adiposity. Stage 1 doesn't mean someone has cardiovascular disease — it identifies an early risk state where prevention and risk-factor modification have substantial potential leverage.

Stage 2 — Metabolic risk factors or chronic kidney disease. Stage 2 means the effects have moved beyond adiposity alone. It can include conditions such as hypertension, high triglycerides, metabolic syndrome, type 2 diabetes, or moderate- to high-risk chronic kidney disease. Someone doesn't need to have all of these — the presence of qualifying metabolic risk factors or kidney disease can be enough.

Stage 3 — High-risk CKM. This is more nuanced than simply "early heart disease." Stage 3 includes people with subclinical cardiovascular disease — cardiovascular abnormalities detectable before a clinical event — as well as people whose predicted cardiovascular risk is sufficiently high or whose kidney disease places them at very high risk.

Under the 2026 guideline, a predicted 10-year cardiovascular disease risk of 20% or more using the AHA's PREVENT equations is one way someone can meet Stage 3 criteria. Very-high-risk chronic kidney disease can also qualify. In other words, Stage 3 describes someone who hasn't necessarily had a heart attack or stroke but whose cardiovascular risk has become substantially more serious.

Stage 4 — Clinical cardiovascular disease. Stage 4 is established cardiovascular disease in the context of CKM syndrome. That can include coronary heart disease, stroke, peripheral arterial disease, heart failure or atrial fibrillation. Kidney failure may also be present. By this stage, the framework is no longer simply identifying future risk.

Why Staging Changes the Conversation

The important idea isn't the acronym. It's the continuum.

Traditional prevention often asks whether someone has a disease. CKM asks an earlier question: where are they on the pathway towards it?

That's why the 2026 guideline recommends CKM staging for both young people and adults. The intention is to prevent progression, tailor treatment to someone's absolute risk and, where possible, move people towards a lower-risk stage through changes such as improved diet, physical activity, weight management and appropriate medical treatment.

It also encourages clinicians to look beyond the organ immediately in front of them. Kidney function becomes relevant to cardiovascular prevention. Abdominal adiposity becomes relevant to kidney risk. Diabetes treatment becomes part of cardiovascular and kidney protection. The boundaries between specialties become less useful.

This Is Now More Than an AHA Concept

That distinction is important. When CKM syndrome was introduced in 2023, it was a new conceptual framework.

In June 2026, it became the subject of the first comprehensive clinical practice guideline for CKM syndrome, produced jointly through the American cardiovascular guideline process with collaboration from major diabetes and kidney organisations.

The guideline recommends routine assessment of metabolic risk factors and kidney function in adults. For chronic kidney disease, that includes both estimated glomerular filtration rate — eGFR, the kidney number many people will recognise from blood-test results — and urine albumin-to-creatinine ratio, or UACR. It recommends measuring both BMI and waist circumference when assessing adiposity. It also incorporates the AHA's newer PREVENT equations, which can estimate 10- and 30-year risk of cardiovascular disease, including both atherosclerotic cardiovascular disease and heart failure, in adults for whom the calculator is appropriate.

And rather than having cardiology, nephrology and endocrinology operate entirely independently, the guideline explicitly recommends interdisciplinary care when these conditions overlap. CKM has therefore moved from describing a problem to influencing how clinicians are being advised to assess it.

Modern Drugs Are Crossing the Same Boundaries

There's another reason this framework has arrived now. Some of the most important medicines introduced or expanded in recent years don't fit neatly into the old speciality silos either.

SGLT2 inhibitors began as glucose-lowering drugs for type 2 diabetes but are now also used because of their cardiovascular and kidney benefits. GLP-1-based therapies can affect body weight and blood glucose while also reducing cardiovascular risk in appropriate patients.

The 2026 CKM guideline incorporates these therapies according to the combination of conditions a person has rather than treating glucose, kidneys and cardiovascular risk as unrelated targets. That doesn't mean everyone with early CKM should be taking medication. It means the treatment landscape itself increasingly reflects the same biological reality as the CKM framework.

Then Came the Study of 23-Year-Olds

This is where the abstract framework becomes much more tangible.

On 20 August 2026, researchers published a study examining CKM health in 1,283 young adults in the United States. Their average age was just 22.9 years.

The researchers classified participants using the AHA CKM framework and also assessed their cardiovascular health using Life's Essential 8 — measures covering diet, physical activity, nicotine exposure, sleep, weight, cholesterol, blood sugar and blood pressure. They then used carotid ultrasound to look for early changes in the arteries.

The CKM breakdown was:

• 7% — Stage 0
• 2% — Stage 1
• 2% — Stage 2
• 8% — Stage 3
• 0% — Stage 4

Put another way, 79.3% were at Stage 1 or above. That's the number that generated headlines. But it needs considerable context.

No, This Doesn't Mean 80% of People in Their Twenties Have Heart Disease

First, this wasn't a nationally representative sample of young Americans. The cohort was deliberately diverse and included a substantial proportion of participants from disadvantaged backgrounds. The researchers themselves caution that the findings may therefore not generalise to all young adults.

It was also a cross-sectional study. Researchers measured CKM stage and arterial characteristics at the same point in time. That allows them to identify associations, but it can't establish that being at a particular CKM stage caused the arterial changes they observed.

And most importantly, the 79.3% figure combines very different levels of risk. More than half of those classified as having CKM were at Stage 1 — excess or dysfunctional adiposity, not diagnosed cardiovascular disease. Only 2.8% were Stage 3. Nobody was Stage 4.

So saying "eight in ten young adults had CKM syndrome" is technically consistent with the staging framework but easily misunderstood. It does not mean eight in ten had heart disease.

The Artery Finding Is More Interesting Than the 79%

The more consequential result sits deeper in the study.

Researchers found that progressively higher CKM stages were associated with poorer Life's Essential 8 cardiovascular-health scores. They also found differences in the carotid arteries. Compared with Stage 0, participants at Stages 1, 2 and 3 had greater carotid intima-media thickness — a measure obtained using ultrasound of the artery wall and used as a marker of early arterial injury. The difference increased across the stages.

For maximum carotid intima-media thickness, the adjusted difference compared with Stage 0 was approximately:

• 014 mm at Stage 1
• 020 mm at Stage 2
• 100 mm at Stage 3

Again, the study cannot prove that CKM stage caused those differences. But finding an association between increasingly advanced CKM stages and measurable arterial changes in people with an average age of 23 is much more informative than the headline prevalence number alone.

Cardiovascular disease usually becomes clinically obvious decades later. The biological processes leading towards it can begin much earlier — one reason biological age and chronological age can diverge so widely.

Is 79% Really That Unusual?

Perhaps less than it initially appears.

A nationally representative analysis of 10,762 US adults using data collected between 2011 and 2020 previously estimated 10.6% at Stage 0, 25.9% at Stage 1, 49.0% at Stage 2, 5.4% at Stage 3 and 9.2% at Stage 4.

In other words, only around one in ten US adults met Stage 0 criteria. Even among adults aged 20 to 44, only 18.2% were at Stage 0 in that analysis.

That doesn't prove the new young-adult study represents the whole population. It does show that early CKM risk factors are hardly unusual. And that's partly the point of creating a framework that starts before disease.

What This Actually Means

CKM syndrome isn't one new disease. It's an umbrella clinical framework designed to recognise that metabolic health, kidney function and cardiovascular disease form an interconnected spectrum.

Stage matters enormously. Stage 1 does not mean the same thing as Stage 4. Someone with excess abdominal adiposity and otherwise normal metabolic health shouldn't interpret the CKM label as meaning they have cardiovascular disease.

The framework has become more clinically significant in 2026. This year's first comprehensive CKM guideline recommends staging across the life course, routine assessment of metabolic and kidney health and more integrated management when conditions overlap.

The 79.3% figure shouldn't be generalised to every 23-year-old. It comes from one US cohort that deliberately included many people from disadvantaged backgrounds.

The arterial findings deserve more attention than the headline percentage. More advanced CKM stages were associated with measurable signs of early arterial injury in people barely into their twenties.

And you probably already recognise most of the measurements involved: blood pressure, blood glucose, cholesterol, weight, waist circumference, kidney function. CKM's novelty isn't that medicine has suddenly discovered these measures. It's that it is increasingly being asked to interpret them as parts of the same system.

If you're working on the everyday inputs behind those numbers — movement, food, sleep and stress — The Reset Programme and Reset Companion can help you build them into a routine you actually keep.

Frequently Asked Questions

What does CKM syndrome stand for?

Cardiovascular-kidney-metabolic syndrome. It describes the interconnected relationship between metabolic risk factors, chronic kidney disease and cardiovascular disease.

When was CKM syndrome introduced?

The American Heart Association introduced the CKM framework in 2023. In June 2026, the first comprehensive clinical practice guideline for preventing, detecting, evaluating and managing CKM syndrome was published.

Is CKM syndrome a disease?

It is better understood as an interconnected clinical syndrome and staging framework than as one disease with one cause, test or treatment. It encompasses people with early metabolic risk through to those with established cardiovascular disease.

What are the five stages of CKM syndrome?

Stage 0 means no CKM risk factors. Stage 1 involves excess or dysfunctional adiposity. Stage 2 includes metabolic risk factors or chronic kidney disease. Stage 3 represents high-risk CKM, including subclinical cardiovascular disease, very-high-risk kidney disease or sufficiently high predicted cardiovascular risk. Stage 4 means established cardiovascular disease in the context of CKM.

What does CKM Stage 1 mean?

Stage 1 means excess or dysfunctional adiposity without the metabolic or kidney abnormalities characteristic of later stages. It identifies an early point at which preventing progression is a priority.

Do nearly 80% of young adults really have CKM syndrome?

One 2026 study of 1,283 US young adults found 79.3% at Stage 1, 2 or 3. But the cohort wasn't nationally representative and included many people from disadvantaged backgrounds, so the figure shouldn't be interpreted as meaning 79.3% of all young adults have CKM syndrome.

What did the young-adult study actually find?

• 7% were Stage 0, 40.2% Stage 1, 36.2% Stage 2 and 2.8% Stage 3. None were Stage 4. Higher CKM stages were also associated with poorer overall cardiovascular health and greater evidence of early arterial injury.

How is CKM risk assessed?

Relevant measurements can include BMI, waist circumference, blood pressure, blood glucose, blood lipids and kidney function. The 2026 US guideline also uses cardiovascular risk prediction in appropriate adults. Exactly how an individual should be assessed depends on age and medical history.

Can CKM stage improve?

The 2026 guideline explicitly includes preventing progression and promoting regression of CKM stage among its aims. Lifestyle changes, weight management and appropriate treatment of blood pressure, diabetes, kidney disease and other risk factors can all form part of that approach depending on the individual.

The Bottom Line

CKM syndrome didn't uncover a new organ or discover a disease nobody knew existed. Its significance is conceptual.

Heart disease, kidney disease, obesity, diabetes, blood pressure and metabolic dysfunction have traditionally been divided across different specialties and different appointments. The CKM framework asks clinicians to see the connections.

That idea was proposed by the American Heart Association in 2023. In 2026, it became considerably harder to dismiss as another medical acronym. The first comprehensive clinical guideline now recommends CKM staging across the life course and integrated assessment of cardiovascular, kidney and metabolic health.

And the new young-adult study provides an unusually clear illustration of why. Its headline finding — 79.3% at Stage 1 or above — needs context. It comes from one non-nationally representative cohort, and 40.2% of participants were only at the earliest CKM stage.

The more revealing finding is that, at an average age of 23, increasingly advanced CKM stages were already associated with measurable differences in the arteries. Heart disease may be diagnosed decades later. The processes that lead towards it don't necessarily wait until middle age to begin.

This is general information rather than medical advice. CKM staging requires interpretation of multiple health measures and risk factors. If you're concerned about your cardiovascular, kidney or metabolic health, speak to your GP or another qualified healthcare professional.

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