Adequacy of Glycemic Control in Hemodialysis Patients W...

Adequacy of Glycemic Control in Hemodialysis Patients With Diabetes

Adequacy of Glycemic Control in Hemodialysis Patients With Diabetes
2006
Daniel J. Tascona, MD, A. Ross Morton, MD, Edwin B. Toffelmire, MD, David C. Holland, MD and Eduard A. Iliescu, MD
Diabetes Care
© 2006 by the American Diabetes Association

Clinical Care/Education/Nutrition
Original Article

From the Division of Nephrology, Department of Medicine, Queen’s University, Kingston, Ontario, Canada

Address correspondence and reprint requests to Eduard A. Iliescu, Queen’s University, 2058 Etherington Hall, Kingston, Ontario, Canada, K7L 3N6. E-mail: eai1@post.queensu.ca

OBJECTIVE—We sought to measure the prevalence of inadequate glycemic control in prevalent hemodialysis patients with diabetes and to examine independent predictors of inadequate glycemic control in these patients.

RESEARCH DESIGN AND METHODS—This is a cross-sectional study of prevalent hemodialysis patients with diabetes in southeastern Ontario (n = 100). Data were collected by chart review and interview. The outcome variable was inadequate glycemic control defined as HbA1c (A1C) >0.07. Other measured variables were diabetes type, diabetes duration, diabetes physician, blood glucose monitoring, diabetes medications, BMI, time on dialysis, and other demographic, clinical, and laboratory variables.

RESULTS—Fifty-four patients had A1C >0.07. In bivariate analysis, these patients had a longer diabetes duration (23.6 vs.14.7 years, P < 0.001), higher proportion with insulin use (81.5 vs. 58.7%, P = 0.012), higher proportion with microvascular complications (66.7 vs. 43.5%, P = 0.017), and lower erythropoietin (EPO) dose (7.0 vs. 11.9 x 103 units/week, P < 0.01) than patients with adequate glycemic control. There was no difference between the two groups in terms of macrovascular complications (59.3 vs. 65.2%, P = 0.54). In multiple logistic regression controlling for age and diabetes type, the diabetes duration (odds ratio 1.09 [95% CI 1.04–1.15], P < 0.001), EPO dose (0.90 [0.85–0.97], P < 0.01), and blood glucose monitoring (10.06 [1.03–98.74], P = 0.05) were the only significant independent predictors of A1C >0.07.

CONCLUSIONS—A high proportion of hemodialysis patients with diabetes had inadequate glycemic control, particularly those with longstanding disease. Patients with inadequate glycemic control had a significantly higher burden of microvascular complications.

Abbreviations: CKD, chronic kidney disease • DCCT, Diabetes Control and Complications Trial • EPO, erythropoietin • ESKD, end-stage kidney disease • KGH, Kingston General Hospital • UKPDS, U.K. Prospective Diabetes Study

INTRODUCTION

The Diabetes Control and Complications Trial (DCCT) and the U.K. Prospective Diabetes Study (UKPDS) showed that maintaining blood glucose at normal or near-normal levels can reduce the incidence of microvascular complications in patients with type 1 and type 2 diabetes, respectively (1,2). Both trials excluded patients with end-stage kidney disease (ESKD) from the study population. A significant percentage of diabetic patients have ESKD, however, and poor glycemic control has been shown to be a predictor of mortality in diabetic patients starting hemodialysis (3). Maintaining euglycemia may also be more difficult in patients with ESKD, as it has been suggested ESKD itself may induce insulin resistance (4).

Using HbA1c (A1C) as a marker of long-term glycemic control in patients with ESKD was problematic in the past, as carbamylated hemoglobin formed in the uremic milieu interfered with older assays that relied on ion exchange for determination of A1C (5,6). Newer chemical and immunoassays do not have this problem (7,8).

A study conducted prior to the results of the DCCT and UKPDS trials did demonstrate an increase in both micro- and macrovascular complications in diabetic patients with poor glycemic control on chronic dialysis (hemodialysis or peritoneal dialysis) but utilized one of these older A1C assays (9). It also set a cutoff for adequate glycemic control of A1C <0.10, well above modern guidelines (10,11). Since the publication of the DCCT and UKPDS trials, there have been no studies showing how patients with diabetes on hemodialysis have fared in terms of adequacy of glycemic control and whether there are any differences between those who do and do not have adequate control.

The primary objective of this study was to measure the prevalence of inadequate glycemic control in prevalent hemodialysis patients with diabetes. The secondary objective was to examine independent predictors of inadequate glycemic control in these patients.

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