Kidney Disease: Risk Factors and Screening

Chronic kidney disease (CKD) is a major public health concern, affecting more than 35 million adults in the United States, with the vast majority undiagnosed. Kidney disease tends to produce no symptoms until very late stages, when the kidneys are approaching failure or when large amounts of protein are present in the urine. This silent progression is the primary reason that only approximately 10% of people with CKD are aware of their condition.

Several risk factors drive CKD development, including diabetes, hypertension, cardiovascular disease, smoking, older age, and obesity. These factors frequently coexist and interact, compounding their effects. Global studies indicate that CKD prevalence is roughly threefold higher in individuals with hypertension, diabetes, or cardiovascular disease compared to the general population. Early detection and management can prevent or delay disease progression by half, and in some cases may even reverse it. Because the condition develops silently, targeted screening based on risk factors is essential for catching it early.

Diabetes and hypertension are the two most strongly established risk factors for CKD and represent the primary screening targets alongside age over 60. Other risk factors include cardiovascular disease, obesity, and family history of kidney disease. While cardiovascular disease, family history, and membership in certain racial and ethnic minority groups are important predictors, diabetes, hypertension, and older age remain the dominant drivers of screening recommendations.

Aging itself contributes to kidney function decline, as glomerular filtration rate decreases by roughly 8 mL/min per decade after the fourth decade of life. Additional factors that may increase kidney disease risk include autoimmune disorders, genetic conditions like polycystic kidney disease, recurrent urinary tract infections, kidney stones, and long-term use of certain medications (particularly NSAIDs). Lifestyle factors such as smoking and excessive protein intake may also contribute to kidney damage over time.

Screening should target high-risk individuals, as this is when treatment is most effective. People with hypertension, diabetes, cardiovascular disease, or age greater than 50 should be prioritized for kidney function screening. CKD is diagnosed and risk-stratified using estimated glomerular filtration rate (eGFR) calculated from serum creatinine and urine albumin-to-creatinine ratio (UACR).

Testing should be considered when risk factors for kidney disease are present, including diabetes, high blood pressure, cardiovascular disease, a family history of kidney problems, or age over 60. At-risk individuals with normal screening results (eGFR at or above 60 and UACR below 30 mg/g) should be rescreened annually. Those experiencing persistent changes in urination, unexplained swelling, or chronic fatigue should also consider testing, as these symptoms may indicate declining kidney function.

An eGFR of 60 or above, combined with a normal urine albumin test, falls within the normal range. An eGFR below 60 may indicate kidney disease, while an eGFR below 15 may indicate kidney failure. A urine albumin result of 30 or above may suggest kidney disease. Results outside normal ranges do not automatically indicate serious kidney impairment but do signal the need for further evaluation and monitoring.

Even with a normal eGFR, the presence of albumin in the urine can indicate early kidney damage. A higher urine albumin-to-creatinine ratio reflects more significant kidney involvement. Healthcare providers typically repeat abnormal tests to confirm findings and may recommend additional evaluation to determine the underlying cause. Early detection enables interventions, including blood pressure and blood sugar management, medication adjustments, and lifestyle changes, that can slow disease progression and reduce the risk of complications.

Maintaining kidney health involves several strategies that can help prevent kidney disease or slow its progression. Managing blood pressure and diabetes through diet, exercise, and medication adherence is crucial, as these are the two leading causes of CKD. A kidney-friendly diet typically involves limiting sodium, processed foods, and excessive protein while emphasizing fruits, vegetables, whole grains, and adequate hydration.

Regular physical activity helps control weight, blood pressure, and blood sugar. Avoiding smoking and limiting alcohol consumption protect the blood vessels that supply the kidneys. Over-the-counter pain medications, particularly NSAIDs, should be used sparingly and only as directed, as chronic use can damage kidney tissue. Regular laboratory monitoring allows for early detection and timely intervention when kidney function begins to decline, making both lifestyle modifications and medical treatments more effective.