Dialysis Trips Up Standard Diabetes Monitoring

Dialysis Trips Up Standard Diabetes Monitoring

By Crystal Phend, Senior Staff Writer, MedPage Today
June 03, 2011


MedPage Today Action Points
Explain that conventional glucose control monitoring methods may not be as meaningful in diabetes patients with end-stage renal disease (ESRD).

Note that a novel measure -- glycated albumin -- more accurately predicted death and hospitalizations in patients with diabetes and ESRD compared with hemoglobin A1c and serum glucose monitoring.

Review
Conventional glucose control monitoring methods may not be as meaningful in diabetes patients with end-stage renal disease, researchers found.

Hemoglobin A1c and serum glucose didn't consistently predict survival or hospitalizations in this population, whereas a novel measure -- glycated albumin -- did, Barry I. Freedman, MD, of Wake Forest University in Winston-Salem, N.C., and colleagues reported online in the Clinical Journal of the American Society of Nephrology.

While recommended by the American Diabetes Association for diabetes diagnosis and clinical monitoring, hemoglobin A1c can be falsely low for patients on dialysis, Freedman's group had previously shown.
Low hemoglobin A1c in these patients may not reflect better longer-term glucose control, but instead that their red blood cells don't survive as long because of factors like anemia and blood loss during dialysis.

Albumin, on the other hand, has a normal life span with dialysis, Freedman explained in an interview.

Glycated albumin predominantly reflects glucose levels over the prior 17 days rather than up to 120 days like hemoglobin A1c, and is equally accurate regardless of kidney problems, Freedman noted.

He predicted that the novel assay would become the test of choice for dialysis patients with diabetes if given the green light by the FDA.

Meanwhile, clinicians need to place more emphasis on the actual blood glucose measurements since those wouldn't provide the "false sense of security" like hemoglobin A1c, he recommended.

The study included 444 patients with diabetes getting dialysis at Wake Forest dialysis facilities for end-stage renal disease; they were followed for 2.33 years.

All patients had glycated albumin measured quarterly as a research test, but the results did not guide treatment because they were not given to treating clinicians.

Higher glycated albumin levels became significantly predictive of mortality with adjustment for age, gender, race, and body mass index (P=0.02) but further adjustment for comorbid conditions, demographics, and laboratory values left only a trend (P=0.07).

In the best-fit model for survival, glycated albumin was the only glucose control measure with significant prognostic power, predicting 14% greater risk of death with each 5% rise in glycated albumin.

Random serum glucose measurements didn't sync with survival in any model. Hemoglobin A1c lost its link with survival after adjustment for patient characteristics.

Most patients followed in the study had at least one hospitalization (86.7%).

Hospitalizations were significantly predicted by higher glycated albumin levels and higher glucose levels across all univariate and multivariate models, whereas hemoglobin A1c wasn't predictive in any model.

"Hemoglobin A1c may be a better marker for hospitalization in the general population than in end-stage renal disease because of differences in red blood cell survival," Freedman's group noted in the paper.

Glycated hemoglobin was unique in its "dose-dependent" relationship with hospitalizations.

The highest quintile of glycated albumin was associated a 9.67% risk of hospitalization within 17 days of measurement, compared with 6.23% in the second lowest and 5.90% in the lowest glycated albumin groups (P=0.02 and P=0.03).

The predictive ability for hospitalization within 30 days appeared similar.

While these results "provide strong evidence" for an important role of glycated albumin, the researchers acknowledged that the study was limited by modest sample size and lack of adjustment for dialysis type and adequacy.

The study was supported in part by Asahi Kasei Pharma.

The researchers reported having no conflicts of interest to disclose.

Primary source: Clinical Journal of the American Society of Nephrology
Source reference:
Freedman BI, et al "Glycated albumin and risk of death and hospitalizations in diabetic dialysis patients" Clin J Am Soc Nephrol 2011; DOI: 10.2215/CJN.11491210.
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