Impact of low hemoglobin on the development of contrast-induced nephropathy: A retrospective cohort study.

An increase in the use of iodinated contrast media, such as iohexol, iodixanol, iopamidol and iopromide, occasionally causes contrast-induced nephropathy (CIN) in patients undergoing coronary angiography (CAG) and/or percutaneous coronary intervention (PCI). The present study aimed to assess the effects of low levels of hemoglobin on the development of CIN in patients with normal renal function following CAG/PCI. A total of 841 consecutive patients undergoing CAG/PCI were divided into two groups: Patients with low levels of hemoglobin (male, <120 g/l; female, <110 g/l; n=156) and normal levels of hemoglobin (male, 120-160 g/l; female, 110-150 g/l; n=685). Multiple logistic regression analysis was performed to identify risk factors for CIN, which developed in 14.7% of patients with low levels of hemoglobin (relative risk, 3.07) and 5% of patients with normal levels of hemoglobin (P<0.01). Independent risk factors for developing CIN in patients with low levels of hemoglobin were a contrast media volume ≥200 ml, diuretic usage, low levels of hemoglobin and diabetes mellitus. For the patients with normal hemoglobin levels, the independent risk factors for developing CIN were a contrast media volume ≥200 ml and diuretic usage. The change in serum creatinine in patients with low levels of hemoglobin was significantly greater compared with patients with normal levels of hemoglobin (7.35±22.60 vs. 1.40±12.00; P<0.01). A similar incidence of developing CIN was observed when patients were administered each type of contrast media: Iohexol, iodixanol, iopamidol and iopromide. The optimal cut-off point at which the serum hemoglobin concentration resulted in a high probability of developing CIN was determined as 111.5 g/l in females and 115.5 g/l in males. In conclusion, low levels of hemoglobin were observed to be an independent risk factor for developing CIN. Patients with reduced hemoglobin levels should, therefore, be closely monitored prior to, and during, the administration of iodinated contrast media.