Wisdom Wednesday: Laboratory Trends

During the months of December, January and February we reduce our lab fees to encourage patients to run a yearly profile. The profile changes from year-to-year but basically has become more extensive over the years.

This year’s standard tests include a hemoglobin A1c, comprehensive metabolic profile (fasting glucose, kidney and liver function, electrolytes, etc.), iron profile, ferritin, serum lipids (total cholesterol, triglycerides, HDL, LDL), CRP (C Reactive Protein), homocysteine, thyroid profile, CBC, vitamin D, and urine analysis.

I often add tests like a PSA for men or TPO (thyroid peroxidase) and thyroid auto-antibodies for Hashimoto’s thyroiditis, if the history indicates the need.

As January ends, I’ve spent hours reviewing lab tests and making nutritional recommendations. I typically use laboratory tests to confirm indications from QA testing but also find them valuable to see disease development in the early stages, when it’s relatively easy to correct.

Every year I see patterns emerge from my patient population. When you review 4-5 tests in a day, you can’t help but see certain trends developing. I thought you might enjoy seeing these trends through this clinician’s eyes.

The eGFR or glomerular filtration rate is a measure of kidney function. It’s a relatively new test and I wrote a blog about it last fall. Initially, the test results were only listed if the result was less than 60. This indicates kidney damage. However, levels between 60 and 90 indicate loss of kidney function. Now that most labs actually list the test results, I am finding a higher and higher percentage of patients in that fall in that 60 to 90 range. They are losing microcirculation to the kidney which may be the result of some aspect of metabolic syndrome, especially insulin resistance. However, the more medication a patient takes, the more likely their eGFR will be below 60.

Kidney Disease Can Lead to Diabetes, Not Just the Other Way Around

Kidney disease increases the risk for diabetes, a new study finds. Medical experts already knew that the reverse is true – that diabetes increases the risk for kidney disease. The authors of the new study, though, found that kidney dysfunction can lead to diabetes – and, that a waste product called urea plays a role in the two-way link between the two diseases.

Urea comes from the breakdown of protein in food. Kidneys normally remove urea from the blood, but poor kidney function can lead to increased levels of urea.

The study involved the analysis of medical records over a five-year period for 1.3 million adults who did not have diabetes. About 9% had elevated urea levels, a sign of reduced kidney function. That’s the same rate as in the general population, according to the researchers.

People with high urea levels were 23% more likely to develop diabetes than those with normal urea levels, the study found. The results were published online recently in the journal Kidney International.

“The risk difference between high and low levels is 688 cases of diabetes per 100,000 people each year,” said study senior author Dr. Ziyad Al-Aly. He’s an assistant professor of medicine at Washington University School of Medicine in St. Louis.

“When urea builds up in the blood because of kidney dysfunction, increased insulin resistance and impaired insulin secretion often result,” Al-Aly said.

The findings about the role of urea could help in efforts to improve treatment and possibly prevent diabetes, the researchers said. Urea levels can be lowered in a number of ways, including medication and diet.

Kidney Disease May Boost Risk of Abnormal Heartbeat

People with failing kidneys are at increased risk of developing a life-threatening abnormal heart rhythm, a new report suggests.

Chronic kidney disease can as much as double a patient’s risk of atrial fibrillation, a quivering or irregular heartbeat that can lead to stroke or heart failure, said lead researcher Dr. Nisha Bansal. She is an associate professor of nephrology at the University of Washington’s Kidney Research Institute, in Seattle.

The risk of atrial fibrillation increases as kidney function declines, Bansal said. “We saw the worse your kidney function, the greater your risk of developing atrial fibrillation. Even mild changes in kidney function were strongly linked to atrial fibrillation,” Bansal noted.

The study included data gathered from three separate research projects focused on heart health in the United States. The three projects created a combined pool of almost 17,000 patients with follow-up periods averaging between 8.5 and 12.5 years. None of the participants had atrial fibrillation when first recruited.

People with worse kidney function at the start of the study were more likely to have atrial fibrillation by the end, the researchers found. Those who did worse on the blood test [GFR] were twice as likely to develop an abnormal heart rhythm, while those who did worse on the urine test [urine protein] were 76% more likely.

“We found that kidney function was independent of all other risk factors,” Bansal said.

A poorly functioning kidney can alter blood levels of a number of nutrients needed to maintain proper heart function, such as potassium, vitamin D, calcium and phosphorus, Bansal said.

The kidneys also are responsible for maintaining a steady volume of blood in your body, removing excess fluid by way of urination. “If your kidney function is impaired, your blood volume increases,” Bansal said. “That increased stress on your heart causes it to stretch and can also trigger this abnormal heart rhythm.”

Kidney Disease a Big Contributor to Heart-Related Deaths

Based on data from 188 countries at six time points between 1990 and 2013, the researchers estimated that in 2013, reduced kidney function was associated with 4% of deaths worldwide, or 2.2 million deaths.

More than half of these deaths (1.2 million) were heart-related, while nearly 1 million were caused by kidney failure, according to the report.

The findings provide new insight into the significant impact of kidney disease, also called “renal” disease, and highlight the importance of screening for kidney problems, the study authors said. “Understanding the true health impact of kidney disease on society necessitates considering cardiovascular as well as end-stage renal disease deaths and disability,” said Dr. Bernadette Thomas, of the University of Washington in Seattle. She made her remarks in a news release from the American Society of Nephrology.

The investigators also found that reduced kidney function ranked below high blood pressure, high blood sugar and overweight/obesity, but was similar to high cholesterol, as a risk factor for disability-adjusted life years (the number of years lost due to ill health, disability or early death).