Many People with High Blood Pressure, Diabetes Missing Key Urine Test

High blood pressure and diabetes are leading causes of chronic kidney disease. Yet, two new studies have found that a significant number of people with these conditions are not getting the recommended screening test for kidney disease.

Without treatment and good control of blood sugar levels, diabetes can damage structures within the kidneys. Likewise, high blood pressure can damage kidney blood vessels if it is not kept under control. If not detected early and treated, kidney disease can eventually lead to kidney failure. 

There are an estimated 37 million American adults with chronic kidney disease, and 90% of them do not know they have it. Early signs and symptoms of kidney disease are often vague and can go unnoticed. For this reason, health organizations recommend that people diagnosed with high blood pressure and diabetes have yearly checks for albumin in their urine, also known as albuminuria, which is an early sign of kidney disease. 

The urine albumin-to-creatinine ratio (ACR) is often the preferred test to screen for kidney disease because it can be done on a random spot urine sample and is a sensitive measurement. Even small amounts of albumin in the urine (ACR of 30 mg/g or more), which is sometimes called microalbuminuria, can indicate kidney damage or disease.   

A large study recently published in the journal Hypertension revealed that many people at risk of kidney disease are not getting this simple but important urine test. The study, led by researchers from the Johns Hopkins Bloomberg School of Health, analyzed data on more than 3 million people from around the world.

For the study, the researchers reviewed the records of over 1 million adults with diabetes and over 2 million adults with high blood pressure but not diabetes. They looked to see how many of these people received a urine ACR to screen for kidney damage within a two-year time period. The scientists found that only about 4% of the people with hypertension and about 35% of the people with diabetes had an ACR within a two-year time frame. 

Another recent study, published in Diabetes Care, examined data collected in the U.S. between 2013 and 2019 and found similar results. The researchers analyzed data from a national reference laboratory on patients diagnosed with diabetes or hypertension to see if they received yearly screening for kidney disease, which included an ACR as well as another measure of kidney function, the estimated glomerular filtration rate (eGFR).    

The researchers identified over 28 million patients as being at risk for kidney disease. About 16% had diabetes, almost 64% had hypertension, and about 20% had both conditions. Overall, about 80% of these patients did not receive the recommended yearly screening for kidney disease during the study timeframe. Of the patients who had testing done, only about 21% had an ACR test, while 89% had an eGFR test performed.

“The common eGFR test alone is insufficient for kidney disease detection,” National Kidney Foundation Chief Medical Officer Joseph Vassalotti, MD, a co-author of the study, said in an NKF news article. “Both the eGFR blood test for kidney function and the uACR urine test for albumin, a type of protein, should be performed at least annually for at-risk patients by primary care physicians and other clinicians who manage diabetes and hypertension, such as endocrinologists and cardiologists.”

Without screening to detect early kidney damage, people with hypertension and/or diabetes may not receive treatments that can reduce their risk or slow progression of the kidney disease. Findings from these two extensive studies demonstrate the need for raising awareness of kidney disease risk and implementing more widespread testing among those at increased risk.

“There are new treatments for patients with albuminuria, including a class of drugs called SGLT2 inhibitors, which appear to be quite effective in protecting the kidneys. . .,” the Hypertension study author Jung-Im Shin, MD, an assistant professor in the Department of Epidemiology at the Bloomberg School of Health, said in a press release. “Our findings suggest that albuminuria screening should be used much more often for detecting chronic kidney disease early, so that patients can benefit from earlier treatment.”