Kidney Disease — Risk Factors and Screening

Chronic kidney disease (CKD) is a major public health issue worldwide, affecting more than 35 million adults in the United States, and most are undiagnosed. Those with kidney disease tend not to experience symptoms until the very late stages, when the kidneys are failing or when there are large amounts of protein in the urine. This is one of the reasons why only 10% of people with chronic kidney disease know that they have it.

There are several risk factors for CKD including diabetes mellitus, hypertension, cardiovascular disease (CVD), smoking, older age, and obesity. Risk factors of CKD often coexist and interact in their effects. A global study indicated that the prevalence of CKD is threefold higher in individuals with hypertension, diabetes, or CVD (high-risk cohorts) than in the general population. Early detection and management of CKD can prevent or delay the disease progression by half or may even reverse it. However, because the condition often develops silently, targeted screening based on risk factors becomes crucial for early identification and intervention.

Diabetes and hypertension are well-established risk factors with a strong link to CKD. Other risk factors for CKD include older age, cardiovascular disease, obesity, and family history. Diabetes, hypertension, and age 60 or greater are the primary CKD screening target conditions. Although cardiovascular disease, family history of CKD, and ethnic and racial minorities are important predictors of CKD risk, they do not contribute significantly beyond the scope of diabetes, hypertension, and older age.

Older people are overly affected by CKD as the glomerular filtration rate (GFR) is reduced by roughly 8 mL/min every 10 years 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 certain medications when used long-term. Lifestyle factors such as smoking and excessive protein intake may also contribute to kidney damage over time. Understanding these risk factors is essential for determining who should be screened and how often monitoring should occur.

Screen your high-risk patients early for CKD, when treatment is most effective. Focus screening efforts on high-risk patients, such as those with high blood pressure, diabetes, and cardiovascular disease. Populations at risk for CKD, such as those with hypertension, diabetes, and age greater than 50 years should be targeted for screening. CKD is diagnosed and risk stratified with estimated glomerular filtration rate utilizing serum creatinine and measuring urine albumin-to-creatinine ratio.

Individuals should consider kidney function testing if they have diabetes, high blood pressure, cardiovascular disease, a family history of kidney disease, or are over age 60. At-risk individuals with an eGFR ≥60 mL/min/1.73 m2 and a UACR <30 mg/g should be re-screened annually for eGFR, UACR, glycated hemoglobin (HbA1c), low-density lipoprotein cholesterol, and blood pressure. Those experiencing symptoms like persistent changes in urination, unexplained swelling, or chronic fatigue should also consider testing, as these may indicate declining kidney function that warrants further evaluation.

If your GFR is 60 or more together with a normal urine albumin test, you are in the normal range. If your GFR is less than 60, it may mean you have kidney disease. If your GFR is less than 15, it may mean your kidneys are failing. A urine albumin test result of 30 or above may mean kidney disease. Results outside normal ranges don't automatically indicate serious kidney disease, but they suggest the need for further evaluation and monitoring.

Abnormal kidney function test results may indicate early-stage kidney disease that can often be managed with lifestyle changes and medical treatment. Even if your eGFR is normal, the presence of a protein called albumin in the urine can indicate early kidney damage. A higher uACR means more albumin is present in your urine, which indicates more significant kidney damage. Healthcare providers typically repeat abnormal tests to confirm results and may recommend additional testing to determine the underlying cause. Early detection allows for interventions that can slow or prevent disease progression and reduce the risk of complications.

Maintaining kidney health involves several key lifestyle strategies that can help prevent kidney disease or slow its progression. Managing blood pressure and diabetes through diet, exercise, and medication compliance is crucial, as these are the leading causes of kidney disease. 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 levels.

Avoiding smoking and limiting alcohol consumption are important for kidney health, as these substances can damage blood vessels and impair kidney function. Over-the-counter pain medications like NSAIDs should be used sparingly and only as directed, as chronic use can harm the kidneys. Regular monitoring through laboratory testing allows for early detection and intervention when kidney function begins to decline, making lifestyle modifications and medical treatments more effective.