In the U.S., chronic kidney disease (CKD) affects 37 million people, with hypertension and diabetes responsible for two-thirds of these cases. CKD is also a significant risk factor for developing diabetes, hypertension, or heart disease. Thus, regular screenings are the most effective approach to preventing and detecting CKD early.
- The only way to clinically diagnose CKD is through tests such as simple urine and blood tests.
- Early detection and intervention in CKD are the most effective solutions in delaying disease progression to end-stage kidney disease and improving life expectancy and quality of life.
- Management of CKD is essential in reducing the risk of CKD-related complications, such as diabetes, hypertension, and heart disease.
Early-Stage Kidney Disease
CKD is characterized by irreversible loss of kidney function that may become worse over time. If the damage to the kidneys becomes severe, the kidneys may stop working altogether. In CKD, when the kidneys become damaged, they lose their ability to filter excess fluids and waste products out of the blood.
In early-stage CKD or stage 1 CKD, kidney damage is mild. The kidneys are still functioning well, but there may be signs of damage to the kidneys. In Stage 1 CKD, the estimated glomerular filtration rate (eGFR) is 90 or greater, which is normal. However, there is a presence of protein in the urine.
Most people with stage 1 CKD do not present with any symptoms, which means many do not know they have kidney disease. Some symptoms that may present in stage 1 CKD that physicians may notice include:
- Hypertension (high blood pressure)
- Protein in the urine
- Hematuria (blood in the urine)
- Kidney damage that presents on an ultrasound, kidney biopsy, CT scan, or MRI
- Swelling in the feet or hands
- Urinary tract infections
If CKD continues to progress, kidney failure or end-stage kidney disease (ESKD) may occur, resulting in the kidneys being unable to survive without a kidney transplant or dialysis.
- Low blood pressure (hypotension) with a high heart rate
- Muscle cramps
- Dark-colored urine that has a strong smell
- Loss of appetite
The Importance of Early Detection
CKD is a public health problem as patients with ESKD take up a disproportionate share of worldwide healthcare resources. This is due to many people not knowing that they have CKD until it progresses to later stages. Early detection of CKD patients via regular screening allows healthcare providers to:
- Manage and treat patients to slow or prevent progression to ESKD.
- Allow for timely initiation of dialysis or preparation for kidney replacement.
- Reduce the risks of complications such as heart disease, diabetes, and hypertension.
Early detection of CKD by regular screening for kidney disease, followed by timely treatment and management, may substantially reduce mortality, morbidity, and CKD-associated complications, which may increase patient outcomes and quality of life.
Screening for Kidney Disease
The only way for healthcare providers to know how well the kidneys function is to test them. Kidney disease often has no symptoms until the later stages of the disease. Screening for kidney disease is also essential if the patient has high blood pressure, diabetes, heart disease, or there is a family history of kidney disease.
Markers used to detect CKD
The most common markers used to detect and diagnose early-stage CKD are estimated glomerular filtration rate (eGFR), serum creatinine (sCR), and proteinuria.
Serum creatinine (sCR) is a readily available test that is used in clinical practice to check kidney function. sCR level is a blood test that measures the amount of creatinine in the blood. Creatinine is a waste product in the blood that originates from the muscles. When the kidneys are damaged, the serum creatinine level in the blood increases.
A sCR test’s effectiveness varies with muscle mass, age, sex, diet, and certain medications. As a result, sCR may not provide physicians with an accurate estimation of kidney function.
However, sCR, when used to calculate eGFR, is regarded as the best overall measure of kidney function and is a test that can be used as a screening tool for monitoring and diagnosing CKD. eGFR is considered a mostly reliable test for physicians to understand how well the kidneys are working. eGFR is a measure of how well the kidneys are functioning. This test is an estimated number based on a blood test, body type, sex, and age. eGFR may not be accurate for those younger than 18, very muscular, very overweight, or pregnant.
Proteinuria is a marker for kidney injury and a strong indicator or predictor for disease progression and cardiovascular issues.
Tests for kidney disease
To test for kidney disease, healthcare providers use:
- Spot urine test for albumin-to-creatinine ratio (ACR) to detect albuminuria. When the kidneys are damaged, albumin (a protein) can pass into the urine.
- Serum creatinine to estimate glomerular filtration rate (eGFR). This blood test checks how well the kidneys can filter blood (glomerular filtration).
- Kidney biopsy. A kidney biopsy is a minimally invasive procedure that can be used to determine how severe the kidney problem is, what is causing it, and the best treatment option.
- Kidney ultrasound. This painless and safe test can show kidney stones, tumors, blood flow to the kidneys, abnormal kidney size and shape, or if there are signs of damage or injury to the kidneys.
- Blood urea nitrogen (BUN) test. A blood test is used to measure the amount of urea nitrogen in the blood. Healthy kidneys remove nitrogen from the bloodstream. When the kidneys are damaged, the BUN level increases.
- Urine test. Urine tests are also used to check for complications from kidney disease, such as metabolic acidosis and anemia. Urine tests check for other issues, such as a urinary tract infection (UTI) or a kidney infection.
Ask your healthcare provider about screening for kidney disease, as diagnosing and beginning treatment can help slow disease progression.
Polycystic Kidney Disease Screening
In the U.S., approximately 600,000 people have PKD. Polycystic kidney disease (PKD) is a genetic condition that causes cysts (fluid-filled sacs) to grow on the kidneys. If too many cysts form or get too big, they can damage the kidneys. As PKD cysts form, they slowly cover most of the kidneys, decreasing kidney function, which may lead to kidney failure. PKD may also cause cysts to form in other organs, such as the liver.
There are two major types of PKD:
- Autosomal dominant polycystic kidney disease (ADPKD). ADPKD is the most common form of PKD. Symptoms typically start to show between the ages of 30 and 40 but can begin during childhood. In ADPKD, if one parent carries the disease gene, their child has a 50/50 chance of inheriting the disease.
- Autosomal recessive polycystic kidney disease (ARPKD). ARPKD is a rare form of PKD. Symptoms typically start in childhood and may begin before birth (in utero).
Tests for PKD
PKD is typically diagnosed with an ultrasound as it is the most cost-effective and non-invasive test. A CT scan and MRI may be used to detect smaller cysts that are not found by an ultrasound. An MRI can also be used to monitor and measure the growth of cysts and the kidneys.
In PKD, the number of cysts and their size increases with age. Thus, if a couple of cysts are observed in each kidney of a 30-year-old patient with a family history of PKD, this is a strong indicator of ADPKD.
Genetic testing may be helpful when:
- There is a family history of PKD, and the patient wants to donate a kidney.
- If the patient is younger than 30 with a negative ultrasound, has a family history of CKD, and wants to start a family.
- There is an unclear diagnosis based on imaging tests.
Kidney Disease Screening and Awareness Program
Despite the increasing prevalence of CKD both in the U.S. and worldwide, there is still a need for effective programs to ignite interest in nephrology as a career choice. Harvard College initiated a new program called The Kidney Disease Screening and Awareness Program to increase participation in kidney disease research and increase interest in nephrology career paths.
Panoramic Health is a physician-led, value-based kidney care platform. We are uniquely positioned to understand the needs of both providers and patients. Our innovative and flexible solutions empower practices to successfully transition to and sustain value-based kidney care.