Too much, too little glucose risky in those on dialysis.
PHILADELPHIA - Poor glycemic control is associated with decreased survival in diabetes patients on maintenance hemodialysis, according to a study presented at the meeting.
Not only does too much glucose increase the risk of all-cause and cardiovascular mortality in this patient population, too little does as well, according to Dr. Kamyar Kalantar-Zadeh of the Harbor-UCLA Medical Center in Torrance, Calif.
Although some guidelines, such as those from the National Kidney Foundation Kidney Disease Outcomes Quality Initiative, recommend that diabetic dialysis patients follow the American Diabetes Association targets for glycemic control (hemoglobin [A.sub.1c] less than 7%), "there is no consistent evidence to support these targets in dialysis patients," Dr. Kalantar-Zadeh said, noting that recent studies with different methodologies have reached opposing conclusions.
To determine the predictive value of glycemic control on mortality, Dr. Kalantar-Zadeh and his colleagues evaluated the association between Hb [A.sub.1c] and random serum glucose and survival in a large, contemporary cohort of diabetes patients treated at DaVita dialysis clinics from July 2001 to June 2006 with follow-up through June 2007.
Of 164,789 hemodialysis patients, the investigators identified 54,757 with diabetes for whom Hb [A.sub.1c] data were available, and analyzed death hazard ratios according to Hb [A.sub.1c] values and serum glucose levels, Dr. Kalantar-Zadeh explained. The adjusted all-cause death hazard ratio for baseline Hb [A.sub.1c] increments of 8.0%-8.9%, 9.0%-9.9%, and 10% or greater, respectively, were 1.06, 1.05, and 1.19, compared with a reference Hb [A.sub.1c] value of 7.0%-7.9%; the respective all-cause death hazard ratios for time-averaged HbAIC were 1.11, 1.36, and 1.59, he said, noting that "a similarly consistent increase in cardiovascular mortality" was also observed.
In adjusted models, decreased survival was also directly associated with time-averaged Hb [A sub.1c]levels in the low range, with all-cause-death hazard ratios of1.05,1.08, and 1.35, respectively, for baseline Hb [A.sub.1c] values of 6.0%-6.9%, 5.0%-5.9%, and less than 5%, compared with 7.0%-7.9%, Dr. Kalantar-Zadeh said. Further, the adjusted all-cause-death hazard ratios for time-averaged blood glucose levels of 175-199 mg/dL, 200-249 mg/dL, 250-299 mg/dL, and 300 mg/dL or higher were 1.03, 1.14, 1.30, and 1.66, respectively, compared with the reference range of 150-175 mg/dL.
The results are limited by the fact that Hb [A.sub.1c] levels are known to significantly underestimate glycemic control in hemodialysis patients, Dr. Kalantar-Zadeh acknowledged at the meeting, sponsored by the American Society of Nephrology. Also, "the information on comorbidity in our study was limited to that obtained from Medical Evidence Form 2728, in which co-morbid conditions are significantly underestimated," he said. Lastly, the study data did not include information on diabetes medication adherence.
"It appears that the most beneficial percentage is somewhere inside 6%-8% in this patient population, "although controlled clinical trials to target Hb [A.sub.1c] at 6%-8% are needed to determine the optimal range," he said.
Dr. Kalantar-Zadeh has financial relationships with Abbott, Amgen, DaVita, Fresenius, Otsuka, Shire, for the National Institutes of Health, and the National Kidney Foundation. The study was supported by the National Institute of Diabetes and Digestive and Kidney Diseases.
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|Publication:||Internal Medicine News|
|Date:||Dec 1, 2011|
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