By Aaron Allen, The Seattle Medium
A groundbreaking study led by Dr. Ian de Boer at the University of Washington School of Medicine has uncovered major discrepancies between routine blood sugar tests and real-time glucose levels in patients undergoing dialysis. Using continuous glucose monitors, researchers identified frequent and sometimes severe episodes of both high and low blood sugar that standard lab tests failed to detect.
“This was sort of a first-look study. We’re really trying to see what’s going on when we look at this population with this new continuous glucose monitoring technology and what we found was quite surprising,” said Dr. de Boer, a nephrologist and professor at the UW School of Medicine. “We found in particular a lot of really high blood sugars, also some low ones. The low ones actually tended to happen to people who didn’t have diabetes. So that was the main thing. And then we wanted to understand why.”
Published in September in the Journal of the American Society of Nephrology, the study followed 420 dialysis patients who wore continuous glucose monitors for 10 days. The small sensors, placed on the upper arm or abdomen, recorded glucose readings every five minutes. The data revealed 714 episodes of low blood sugar, including 179 classified as severe. Hypoglycemia occurred most often in non-diabetic patients receiving hemodialysis.
“It was eye-opening because there clearly are abnormalities going on that we are not aware of,” said de Boer. “We presume high and low glucose values matter in this population, but we can’t say for sure. In any case, if I’m a patient on dialysis, I want to get one of these monitors and see what’s going on.”
More than half of dialysis patients have diabetes, and their glucose levels are commonly monitored with the hemoglobin A1C (HbA1c) test, performed every three to six months. This test estimates a patient’s average blood sugar over time. However, its accuracy is reduced in patients with kidney failure.
“In this population of patients, people who are treated with dialysis, the usual test, which is hemoglobin A1C, is off basically, and we’ve known that for a while,” said de Boer. “It’s because of differences in red blood cell turnover, and so it tends to read lower than it should.”
The real-time data showed how misleading HbA1c results can be. Among diabetic patients on glucose-lowering medication, only 22 percent met modern treatment targets, despite showing normal-range A1C values. Even more striking, patients with untreated diabetes also had consistently elevated glucose levels, though their A1C values appeared normal.
“We expected glycemic excursions out of range, but the outlier glucose levels we saw with continuous monitoring, both high and low, were much farther out of range than an A1C would have predicted,” said de Boer.
While the study suggests that continuous glucose monitors could benefit dialysis patients, especially those with diabetes, it did not examine which specific treatments might improve outcomes for patients with unrecognized blood sugar fluctuations.
“We don’t know for sure whether controlling glucose in this population is going to improve wellbeing. More research is needed to address that question,” de Boer said. “There might be multiple benefits of better glucose control. For example, it might prevent heart disease or infections or make someone a healthier candidate for kidney transplant. But we don’t yet know how glucose control stacks up in the list of priorities for patients on dialysis, who already have many demands on their health.”
The research team aims to continue studying why these hidden glucose variations occur in dialysis patients, both with and without diabetes, and how the findings might lead to better clinical care.
“I think the goal is to be able to maintain health. Heart health, vascular health, eye health. It’s to get people in shape for something like a kidney transplant, which can be transformative,” said de Boer. “I think that our goal is to optimize their care in this regard to help achieve those health goals for people and hopefully make the lives of people living with dialysis better.”
