Many patients who will later be diagnosed with diabetes show signs of chronic kidney disease (CKD)even before their diabetes diagnosis, according to a new study

 

Doctors have long known that patients with diabetes are at risk for kidney disease. But the new study shows that patients could be suffering undiagnosed kidney damage even before they are aware that they have diabetes.

Looking at data from Veterans Affairs electronic health records, the researchers found that more than 30 percent of diabetic veterans had prior CKD signs. They also found racial and regional disparities in kidney disease risk.

About 10% of the U.S. population — around 20 million people — have CKD. Diabetes is the leading cause of CKD and end-stage renal disease. One-third of adults with diabetes have CKD. Other conditions that often co-occur with diabetes, such as cardiovascular disease, also raise the risk of kidney disease.

"While CKD is silent, it can also lead to a higher risk of various complications such as high blood pressure, cardiovascular disease, and death. Early recognition of CKD can help implement measures that can delay its progression, and is thus very important. While there are no cures for established CKD, a healthy lifestyle, good blood pressure and diabetes control, and avoidance of various harmful exposures, such as over-the-counter painkillers, can help delay CKD's progression," says the author.

Health care guidelines recommend screening for CKD for at-risk patients. However, patients often are screened only after they are diagnosed with established diabetes.

To assess the risk of kidney damage from undiagnosed diabetes, the researchers looked at data on 36,794 veterans who were diagnosed with diabetes between 2003 and 2013. They found that 31.6% of these veterans had evidence of CKD before the diabetes diagnosis, based on estimated glomerular filtration rate (eGFR) and urine-albumin-creatine ratios, two common measures of kidney function.

The results suggest that kidney damage often occurs before diabetes is diagnosed, say the researchers. They propose two possible reasons for this early kidney damage: Type 2 diabetes can be undiagnosed for a long time, meaning the kidneys are being damaged without the patient or doctors being aware. Or, kidney damage could come from other conditions common in the population at risk for diabetes.

According to the researchers, the results highlight an opportunity for broadening screening among patients with increased risk of CKD. More screening of at-risk populations could lead to earlier identification of diabetes, which could, in turn, prevent organ damage.

The study also revealed disparities in the rates of CKD based on race. Asian Americans and African Americans had higher rates of chronic kidney disease than whites. However, the proportion of patients who were minorities decreased as disease severity increased.

These results based on racial group differ somewhat from the results of other studies. African Americans and Hispanics have generally been shown to have higher rates of CKD than whites. The disease also tends to progress faster in these populations. But results in this study did not show a higher risk for Hispanics. More advanced kidney disease also had a more even racial distribution, according to the new data.

Kovesdy says, "Better awareness of the risk factors for CKD — for example, high blood pressure, obesity, cardiovascular disease, race-ethnicity, family history — is needed for health care providers to become proactive about screening for early-stage CKD."

The study was funded by VA and the University of Tennessee Health Science Center Institute for Research, Innovation, Synergy, and Health Equity.