Hemoglobin A1c Levels and Mortality in the Diabetic Hemodialysis Population
Findings from the Dialysis Outcomes and Practice Patterns Study (DOPPS)
- Sylvia Paz B. Ramirez, MD, MPH, MBA1⇓,
- Keith P. McCullough, MS1,
- Jyothi R. Thumma, MPH1,
- Robert G. Nelson, MD, PHD2,
- Hal Morgenstern, PHD1,3,
- Brenda W. Gillespie, PHD4,
- Masaaki Inaba, MD, PHD5,
- Stefan H. Jacobson, MD, PHD6,
- Raymond Vanholder, MD, PHD7,
- Ronald L. Pisoni, PHD, MS1,
- Fritz K. Port, MD, MS1,4 and
- Bruce M. Robinson, MD, MS, FACP1,4
- 1Arbor Research Collaborative for Health, Ann Arbor, Michigan
- 2Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, Arizona
- 3Departments of Epidemiology and Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, Michigan
- 4University of Michigan, Ann Arbor, Michigan
- 5Osaka City University, Osaka, Japan
- 6Department of Nephrology, Karolinska Institutet, Danderyd University Hospital, Stockholm, Sweden
- 7Nephrology Division, Ghent University Hospital, University of Ghent, Ghent, Belgium
- Corresponding author: Sylvia Paz B. Ramirez, .
OBJECTIVE Lowering hemoglobin A1c to <7% reduces the risk of microvascular complications of diabetes, but the importance of maintaining this target in diabetes patients with kidney failure is unclear. We evaluated the relationship between A1c levels and mortality in an international prospective cohort study of hemodialysis patients.
RESEARCH DESIGN AND METHODS Included were 9,201 hemodialysis patients from 12 countries (DOPPS 3 and 4, 2006–2010) with type 1 or type 2 diabetes and at least one A1c measurement during the first 8 months after study entry. Associations between A1c and mortality were assessed with Cox regression, adjusting for potential confounders.
RESULTS The association between A1c and mortality was U-shaped. Compared with an A1c of 7–7.9%, the hazard ratios (95% CI) for A1c levels were 1.35 (1.09–1.67) for <5%, 1.18 (1.01–1.37) for 5–5.9%, 1.21 (1.05–1.41) for 6–6.9%, 1.16 (0.94–1.43) for 8–8.9%, and 1.38 (1.11–1.71) for ≥9.0%, after adjustment for age, sex, race, BMI, serum albumin, years of dialysis, serum creatinine, 12 comorbid conditions, insulin use, hemoglobin, LDL cholesterol, country, and study phase. Diabetes medications were prescribed for 35% of patients with A1c <6% and not prescribed for 29% of those with A1c ≥9%.
CONCLUSIONS A1c levels strongly predicted mortality in hemodialysis patients with type 1 or type 2 diabetes. Mortality increased as A1c moved further from 7–7.9%; thus, target A1c in hemodialysis patients may encompass values higher than those recommended by current guidelines. Modifying glucose-lowering medicines for dialysis patients to target A1c levels within this range may be a modifiable practice to improve outcomes.
- Received March 26, 2012.
- Accepted June 5, 2012.
- © 2012 by the American Diabetes Association.
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