Low hemoglobin, chronic kidney disease, and risk for coronary heart disease-related death: the Blue Mountains Eye Study.

A recent report found that chronic kidney disease (CKD) increased the risk for coronary heart disease (CHD) events in people with anemia but not in those without anemia. This study aimed to verify these findings in the Blue Mountains Eye Study cohort, a prospective Australian population-based study of 3654 residents aged 49 to 97 yr. Fasting blood samples were obtained at baseline and confirmed CHD-related deaths over 9 yr with the Australian National Death Index. "Low hemoglobin" was defined as levels in the lowest quintile of the cohort. Body surface area-adjusted GFR was estimated using a variety of methods (Cockcroft-Gault, abbreviated Modification of Diet in Renal Disease, and Bjornsson equations). People with CKD (GFR <60 ml/min per 1.73 m2 as estimated using the Cockcroft-Gault equation) and low hemoglobin (mean 13.2 g/dl; range 7.6 to 14.6 g/dl) had an increased risk for CHD-related death (multivariable-adjusted hazard risk ratio 1.49; 95% confidence interval 1.08 to 2.06) compared with people with CKD but in higher hemoglobin quintiles. This effect was not evident in people without CKD. The interaction between GFR and hemoglobin was significant (P = 0.05) when GFR was estimated using either the Cockcroft-Gault or Bjornsson equations or when serum creatinine instead of GFR was used in the analyses but not when GFR was estimated using the abbreviated Modification of Diet in Renal Disease equation. In conclusion, this study found that low hemoglobin, even within the normal range, together with CKD increased the risk for CHD-related death.