UVA School of Medicine

Off-Shelf Glucose Monitors Prove Accurate for Dialysis Patients I n what is believed to be the first study of its kind, new UVA Health research reveals that a factory- calibrated continuous glucose monitor (CGM) may be sufficiently accurate for use by people on dialysis, a group often plagued by dangerous swings in blood-sugar levels. The findings suggest that factory-calibrated blood glucose monitors could offer an important diabetes- management tool for patients on dialysis and those suffering end-stage renal disease (ESRD). "Patients with end-stage renal disease are often excluded from clinical research trials, as they are medically complex. Therefore, these CGM devices — often considered 'game changers' for patients with diabetes to monitor their sugars — are not yet FDA-approved for patients with ESRD on dialysis," says researcher Meaghan M. Stumpf, MD, who specializes in diabetes and diabetes-management technology at UVA Health. "However, ESRD patients and their physicians may still benefit from their use. Our research team conducted this pilot study so that we could begin to understand the accuracy of these devices for patients with ESRD on hemodialysis. This study is not large enough to lead to FDA approval, but it is important to take the first step." Continuous Glucose Monitors for Dialysis Continuous glucose monitors are becoming widely used by patients with diabetes. These devices allow patients to track their glucose levels automatically, helping them prevent their blood-sugar levels from getting dangerously high or low. Managing blood-sugar levels is a particular challenge for patients on dialysis, a procedure that filters blood for patients whose kidneys can no longer do so adequately. Patients on dialysis often suffer from hypoglycemia, or low blood sugar, which is potentially deadly. That means that these patients need highly reliable, accurate ways to track their blood sugar. Until now, physicians and researchers did not have accuracy data for factory-calibrated continuous glucose monitors, so it was unclear if these devices would be up to the job. To determine this, Stumpf and her colleagues enlisted 20 volunteers receiving hemodialysis at UVA to test such a device, the Dexcom G6-Pro. Most of the participants were male, African American, and on insulin, with an average age of 61. The participants were asked to wear the CGM for 10 days and to take four to seven fingerstick blood-sugar readings per day with a home glucometer. Venous blood samples were also collected during their hemodialysis sessions. The researchers compared the CGM glucose results with the blood-sugar results collected by the patients and during the patients' thrice- weekly dialysis sessions. The researchers determined that the continuous glucose monitor overall showed "clinical reliability," meaning that the device was sufficiently accurate for estimating blood-sugar levels. Almost 99% of the readings were accurate enough to be used without confirmatory fingerstick blood sugar readings. When the devices erred, they tended to overestimate, rather than underestimate, blood-sugar levels, prompting the researchers to note that additional research is warranted, especially considering that people on dialysis tend to be at elevated risk for low blood sugar. "Although we certainly need larger studies, I am encouraged that these factory- calibrated continuous glucose monitors may be reasonably accurate for patients on hemodialysis therapy," Stumpf says. "CGM use for these patients could lead to improved glucose control, improved safety from life-threatening hypoglycemia and, very importantly, improved quality of life." Meaghan M. Stumpf, MD cardiovascular disease and heart failure. As chromosome loss increased, the scientists found, so did the risk of death. Potential Treatment The findings suggest that targeting the effects of Y chromosome loss could help men live longer, healthier lives. Walsh notes that one potential treatment option might be a drug, pirfenidone, that has already been approved by the Food and Drug Administration for the treatment of idiopathic pulmonary fibrosis, a form of lung scarring. The drug is also being tested for the treatment of heart failure and chronic kidney disease, two conditions for which tissue scarring is a hallmark. Based on his research, Walsh believes that men with Y chromosome loss could respond particularly well to this drug, and other classes of antifibrotic drugs that are being developed, though more research will be needed to determine that. At the moment, doctors have no easy way to determine which men suffer Y chromosome loss. Walsh's collaborator Lars A. Forsberg, of Uppsala University in Sweden, has developed an inexpensive polymerase chain reaction (PCR) test, like those used for COVID-19 testing, that can detect Y chromosome loss, but the test is largely confined to his and Walsh's labs. Walsh, however, can foresee that changing: "If interest in this continues and it's shown to have utility in terms of being prognostic for men's disease and can lead to personalized therapy, maybe this becomes a routine diagnostic test," he says. "The DNA of all our cells inevitably accumulate mutations as we age. This includes the loss of the entire Y chromosome within a subset of cells within men. Understanding that the body is a mosaic of acquired mutations provides clues about age-related diseases and the aging process itself," says Walsh, a member of UVA's Department of Biochemistry and Molecular Genetics. "Studies that examine Y chromosome loss and other acquired mutations have great promise for the development of personalized medicines that are tailored to these specific mutations." Fall 2022 7

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