CKM Syndrome Reaches Most Iranian Adults in National Survey
A nationally representative survey from Iran paints a stark picture of cardiovascular-kidney-metabolic (CKM) syndrome: nearly every adult in the study had moved beyond stage 0, and stage 2 was by far the most common category. Among 16,208 adults aged 25 years and older, 94.26% met criteria for CKM stages 1 through 4. Stage 2 alone accounted for 65.73% of participants, while stage 1 made up 13.08%.
The distribution matters because CKM syndrome is not a single disease but a staged continuum linking metabolic risk, cardiovascular injury, and kidney dysfunction. In practical terms, the burden is already concentrated in people who have crossed the threshold from isolated risk factors into a more established multisystem process. Once the vascular, renal, and metabolic pathways begin to converge, the probability of later atherosclerotic and renal complications rises in parallel with worsening blood pressure, glycemic, and lipid abnormalities.
Hypertension and metabolic syndrome emerged as the most prevalent cardiometabolic conditions in the cohort. Moderate- to high-risk and very high-risk chronic kidney disease were the least prevalent categories, suggesting that the national burden at this moment is driven more by upstream cardiometabolic disruption than by advanced kidney failure. Even so, the stage distribution implies a large reservoir of adults at risk for future progression if blood pressure, weight, glucose, diet, and physical activity are not addressed early.
Stage 2 Dominance Signals a Large Reservoir of Preventable Risk
Stage 2 represented the largest share of the population by a wide margin. The staging framework used here captures a transition from risk accumulation to clinically meaningful dysfunction, and the heavy concentration in stage 2 points to widespread exposure to modifiable drivers of disease. In a population where hypertension and metabolic syndrome are already common, the vascular endothelium, renal microcirculation, and insulin signaling pathways are under sustained stress. Over time, that biology feeds a cycle of sodium retention, arterial stiffness, worsening adiposity, and further metabolic deterioration.
The stage pattern also offers a public health message that is difficult to ignore: CKM syndrome is not confined to a small high-risk minority. It appears embedded across the adult population, with a distribution that suggests early detection and risk-factor control will have to operate at scale rather than as narrowly targeted specialty care.
Geographic Clustering Was Not Uniform Across the Country
Clear regional variation appeared across Iran. Northwestern and southwestern provinces showed high prevalence of stage 3, but relatively low prevalence of stage 4. The reason for this pattern is not established by the survey itself, yet the geographic gradient suggests that local differences in lifestyle, access to care, socioeconomic conditions, and chronic disease management may be shaping how CKM progresses across provinces.
Such clustering is clinically important because CKM staging is not just an abstract epidemiologic construct. A province with more stage 3 disease carries a heavier burden of accumulated cardiometabolic injury and a larger population in whom secondary prevention needs to start immediately. The absence of parallel stage 4 concentration in those same regions may reflect differences in survival, referral patterns, earlier detection, or the pace at which patients move from one stage to the next. The data do not resolve that question, but they do identify where surveillance and intervention deserve closer attention.
Unhealthy Lifestyle Factors Rose as CKM Stages Advanced
Lifestyle risk clustered with disease stage, especially in the more advanced categories. In stage 3, 63.83% of participants reported at least two unhealthy lifestyle factors, and 10.19% reported three or more. In stage 4, 57.89% reported at least two unhealthy lifestyle factors, while 11.85% reported three or more.
Insufficient fruit and vegetable intake was the most common unhealthy behavior across all CKM stages. That finding is biologically plausible and clinically familiar. Diet patterns low in plant foods typically track with higher sodium intake, poorer potassium balance, reduced fiber, and a dietary pattern that can worsen weight control, blood pressure, insulin resistance, and lipid metabolism. In a syndrome defined by the interaction of cardiovascular, kidney, and metabolic injury, dietary quality is not a side issue; it is one of the most modifiable inputs into the entire disease process.
The prevalence of multiple unhealthy behaviors in stages 3 and 4 also suggests that advanced CKM is rarely the result of a single isolated exposure. Rather, it tends to develop in the setting of layered risk: poor diet, limited physical activity, and likely long-standing cardiometabolic abnormalities that have not been fully corrected. That combination helps explain why the burden persists even before the most severe kidney categories become common.
National Surveillance May Be More Useful Than Waiting for Advanced Disease
This secondary analysis of the 2021 STEPS survey provides the kind of descriptive evidence that health systems need before they can build a CKM strategy at population level. The survey design cannot establish causality, and it does not prove which risk factor drove which stage. It does, however, show where disease is concentrated, where unhealthy behaviors are common, and where prevention efforts are likely to yield the greatest return.
The public health implication is direct. If stage 2 already contains the majority of the burden, then waiting for overt kidney decline or advanced cardiovascular disease means entering the problem too late. Screening for hypertension, metabolic syndrome, obesity, dysglycemia, and reduced kidney function needs to be paired with aggressive lifestyle counseling, not reserved for patients who have already progressed far enough to require specialty referral.
This analysis also reinforces the value of geographically resolved surveillance. Provincial differences in stage distribution can guide regional prevention campaigns, primary care resource allocation, and earlier cardiometabolic intervention. For Iran, the current data provide a national baseline, but they also leave an important operational question unanswered: whether local health systems can identify stage 2 disease early enough to prevent downstream stage 3 and stage 4 progression.