Hemoglobin A(1c) levels and mortality in the diabetic hemodialysis population: findings from the Dialysis Outcomes and Practice Patterns Study (DOPPS).

OBJECTIVE: Lowering hemoglobin A(1c) 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 A(1c) 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 (Dialysis Outcomes and Practice Patterns Study 3 and 4, 2006-2010) with type 1 or type 2 diabetes and at least one A(1c) measurement during the first 8 months after study entry. Associations between A(1c) and mortality were assessed with Cox regression, adjusting for potential confounders. RESULTS: The association between A(1c) and mortality was U-shaped. Compared with an A(1c) of 7-7.9%, the hazard ratios (95% CI) for A(1c) 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 A(1c) <6% and not prescribed for 29% of those with A(1c) ≥9%. CONCLUSIONS: A(1c) levels strongly predicted mortality in hemodialysis patients with type 1 or type 2 diabetes. Mortality increased as A(1c) moved further from 7-7.9%; thus, target A(1c) in hemodialysis patients may encompass values higher than those recommended by current guidelines. Modifying glucose-lowering medicines for dialysis patients to target A(1c) levels within this range may be a modifiable practice to improve outcomes.

Optimizing hemodialysis practices in Canada could improve patient survival.

Data from the Canadian Organ Replacement Registry (CORR) and the Dialysis Outcomes and Practice Patterns Study (DOPPS) were used to determine whether practice patterns have changed in Canada since the introduction of the Canadian Society of Nephrology (CSN) Guidelines in 1999. DOPPS data were then used to calculate the impact of not meeting the proposed guideline targets and to estimate the potential life years gained if all Canadian hemodialysis patients achieved guideline targets. For dialysis dose and hemoglobin targets, Canadian facility performance has significantly improved over time. The vascular access use patterns show trends toward a worse pattern with increased catheter use. A calculation of the percentage of attributable risk suggests that 49% of deaths could possibly be averted if all patients currently outside the guidelines achieved them over the next five years. This corresponds to a decrease in the annual death rate from 18 to 10.1 per hundred patient years. These data support the need for improved adherence to guidelines. If Canadian caregivers were to optimize practice patterns, patient outcomes could be improved.

DOPPS estimate of patient life years attributable to modifiable hemodialysis practices in Canada.

We examined data from the Canadian Organ Replacement Registry, and from a special substudy of CORR, to determine whether changes have occurred in practice patterns before and after the 1999 Canadian Society of Nephrology guidelines were published. Second, we used data from the Dialysis Outcomes and Practice Patterns Study to calculate the impact of observed deviations from guideline targets and estimated potential gains in life years that might accrue if guideline targets were achieved in all Canadian hemodialysis patients. For dialysis dose and hemoglobin targets, there was a significant improvement in Canadian facility performance over time. On the other hand, vascular access care showed a worse pattern with increased catheter use. A calculation of attributable risk, which assumes causality, suggests that 49 percent of deaths could be averted if all patients currently outside the guidelines achieved them over the next five years. When expressed as an annual death rate per hundred patient years, this corresponds to a decrease from 18 to 10.1 deaths per 100 patient years. We conclude that promoting a facility-based culture of quality improvement based on achievement of guideline targets is supported by international and Canadian observational data from the DOPPS. In the future, the impact of such an approach should be assessed empirically by correlating changes in practice over time with changes in outcomes.