Associations of Glycemic Control With Cardiovascular Outcomes Among US Hemodialysis Patients With Diabetes Mellitus

Background There is a lack of data on the relationship between glycemic control and cardiovascular end points in hemodialysis patients with diabetes mellitus. Methods and Results We included adult Medicare‐insured patients with diabetes mellitus who initiated in‐center hemodialysis treatment from 2006 to 2008 and survived for >90 days. Quarterly mean time‐averaged glycated hemoglobin (HbA 1c ) values were categorized into <48 mmol/mol (<6.5%) (reference), 48 to <58 mmol/mol (6.5% to <7.5%), 58 to <69 mmol/mol (7.5% to <8.5%), and ≥69 mmol/mol (≥8.5%). Medicare claims were used to identify outcomes of cardiovascular mortality, nonfatal myocardial infarction ( MI ), fatal or nonfatal MI , stroke, and peripheral arterial disease. We used Cox models as a function of time‐varying exposure to estimate multivariable adjusted hazard ratios and 95% CI for the associations between HbA 1c and time to study outcomes in a cohort of 16 387 eligible patients. Patients with HbA 1c 58 to <69 mmol/mol (7.5% to <8.5%) and ≥69 mmol/mol (≥8.5%) had 16% ( CI , 2%, 32%) and 18% ( CI , 1%, 37%) higher rates of cardiovascular mortality ( P ‐trend=0.01) and 16% ( CI , 1%, 33%) and 15% ( CI , 1%, 32%) higher rates of nonfatal MI ( P ‐trend=0.05), respectively, compared with those in the reference group. Patients with HbA 1c ≥69 mmol/mol (≥8.5%) had a 20% ( CI , 2%, 41%) higher rate of fatal or nonfatal MI ( P ‐trend=0.02), compared with those in the reference group. HbA 1c was not associated with stroke, peripheral arterial disease, or all‐cause mortality. Conclusions Higher HbA 1c levels were significantly associated with higher rates of cardiovascular mortality and MI but not with stroke, peripheral arterial disease, or all‐cause mortality in this large cohort of hemodialysis patients with diabetes mellitus.