Glycemic Control and Cardiovascular Events in Diabetic Hemodialysis Patients

Abstract

Background— Patients on maintenance dialysis treatment experience an excess mortality, predominantly of sudden cardiac death. Poor glycemic control is associated with cardiovascular comorbidities in the general population. This study investigated the impact of glycemic control on cardiac and vascular outcomes in diabetic hemodialysis patients. Methods and Results— Glycohemoglobin A1c (HbA 1c ) was measured in 1255 hemodialysis patients with type 2 diabetes mellitus who participated in the German Diabetes and Dialysis Study (4D Study) and were followed up for a median of 4 years. Using Cox regression analyses, we determined hazard ratios to reach prespecified, adjudicated end points according to HbA 1c levels at baseline: sudden cardiac death (n=160), myocardial infarction (n=200), stroke (n=103), cardiovascular events (n=469), death caused by heart failure (n=41), and all-cause mortality (n=617). Patients had a mean age of 66±8 years (54% male) and mean HbA 1c of 6.7±1.3%. Patients with an HbA 1c >8% had a >2-fold higher risk of sudden death compared with those with an HbA 1c ≤6% (hazard ratio, 2.14; 95% confidence interval, 1.33 to 3.44), persisting in multivariate models. With each 1% increase in HbA 1c , the risk of sudden death rose significantly by 18%; similarly, cardiovascular events and mortality increased by 8%. There was a trend for higher risks of stroke and deaths resulting from heart failure, whereas myocardial infarction was not affected. The increased risks of both cardiovascular events and mortality were explained mainly by the impact of HbA 1c on sudden death. Conclusions— Poor glycemic control was strongly associated with sudden cardiac death in diabetic hemodialysis patients, which accounted for increased cardiovascular events and mortality. In contrast, myocardial infarction was not affected. Whether interventions achieving tight glycemic control decrease sudden death requires further evaluation. Clinical Trial Registration— URL: http://www.clinicalstudyresults.org. Unique identifier: CT-981–423–239.