When someone is diagnosed with heart disease, tests such as an ECG, echocardiogram, cholesterol profile and blood pressure monitoring naturally become part of regular care. But there is another organ that deserves equal attention: the kidneys.
The heart and kidneys work in close partnership. The heart pumps blood to the kidneys, while the kidneys regulate fluid, electrolytes and blood pressure. Damage to one can place additional stress on the other. The World Health Organization (WHO) notes that kidney disease both causes and is caused by cardiovascular disease, while conditions such as diabetes and hypertension can increase the risk of both.
The problem is that chronic kidney disease (CKD) often develops silently. A person may have significant kidney damage without pain, changes in urination or other obvious symptoms. For people with existing cardiovascular disease, heart failure, hypertension or diabetes, routine kidney screening can therefore be an important part of long-term heart care.
1. Serum creatinine and eGFR
A routine blood test can measure serum creatinine, a waste product normally removed by the kidneys. Doctors use the creatinine result along with other factors to calculate the estimated glomerular filtration rate (eGFR), an estimate of how efficiently the kidneys filter blood.
An eGFR below 60 mL/min/1.73 m2 that persists for at least three months can indicate CKD. However, one abnormal result does not automatically mean chronic kidney disease and needs clinical interpretation and, where appropriate, repeat testing.
2. Urine albumin-to-creatinine ratio
The urine albumin-to-creatinine ratio (uACR) is one of the simplest ways to look for early kidney damage. Healthy kidneys retain albumin, a blood protein. When the kidney's filtering barrier is damaged, albumin can leak into urine. A uACR above 30 mg/g can indicate kidney damage, even when eGFR is still above 60. Persistent albuminuria therefore should not be dismissed simply because the blood test appears normal.
Importantly, eGFR and uACR provide complementary information. The 2024 KDIGO CKD guideline recommends assessing both kidney filtration and albuminuria because each contributes to risk assessment.
3. Blood pressure
Blood pressure is both a heart and kidney health marker. Long-standing high blood pressure can damage the small blood vessels inside the kidneys, while declining kidney function can make blood pressure harder to control.
For this reason, persistently high or difficult-to-control blood pressure should prompt discussion about kidney evaluation. The American Heart Association also includes kidney function and urine albumin testing among important cardiovascular-kidney-metabolic health checks.
4. Blood glucose or HbA1c
Diabetes is a major risk factor for both cardiovascular and kidney disease. Elevated blood glucose can progressively damage the kidney's filtering units, with albuminuria often appearing early. The American Diabetes Association recommends at least annual eGFR and uACR assessment for people with type 2 diabetes.
5. Routine urinalysis
A basic urine examination can provide additional clues, including the presence of blood, protein or other abnormalities. While it does not replace uACR and eGFR for CKD assessment, it can help doctors decide whether further evaluation is needed.
Why this matters for heart patients
Detecting CKD is not simply about preventing dialysis. Reduced kidney function and albuminuria are associated with higher risks of cardiovascular events, including heart attack, stroke and heart failure.
The 2026 American Heart Association cardiovascular-kidney-metabolic health guidance specifically recommends using both eGFR and uACR to identify CKD and guide kidney- and heart-protective treatment. For a heart patient, kidney screening need not mean an elaborate battery of tests. Two particularly important checks are a blood test for creatinine/eGFR and a urine test for uACR, supported by regular monitoring of blood pressure, blood glucose and routine urinalysis when clinically appropriate.
If you have heart disease, heart failure, high blood pressure or diabetes, ask your doctor whether your kidney function and urine albumin have been checked recently. Finding kidney disease early can create an opportunity to protect both kidney function and cardiovascular health.
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