Iron storage indices and risk of bacterial infections in hemodialysis patients

Abstract

Infection is the second leading cause of death among hemodialysis (HD) patients. Because iron overload may be a risk factor for bacterial infection, concerns about excessive use of intravenous (IV) iron have arisen. In this retrospective analysis, we explored the relationship between target iron storage indices, as outlined in the Dialysis Outcomes Quality Initiative (DOQI) guidelines, and the incidence of bacterial infections. We reviewed the charts of 87 HD patients who received their first course of IV iron at our dialysis unit between 1997 and 2001. Transferrin saturation (TSAT) rate, ferritin level, and other clinical/laboratory measures were recorded at baseline. Patients were followed for up to 2 years for the outcomes of bacteremia and bacterial pneumonia and censored at death, end-of-study observation, or kidney transplantation. Cox proportional hazards regression was used to evaluate the relationship of bacterial infections to iron storage indices. Thirty-two patients had at least one episode of bacterial infections. In multivariate analyses, after adjusting for sex and venous catheter use, iron-replete state (ferritin > 100 ng/mL and TSAT > 20%) was associated with a threefold higher risk of bacterial infections (95% CI 1.3-6.6; p = 0.01). Although diabetes mellitus and lower serum albumin had a nonsignificant trend toward an increased risk of bacterial infections, no such relationship was seen with the first 3-month cumulative IV iron dose. This study suggests an increased risk for bacterial infections at modest levels of iron stores (ferritin > 100 ng/mL and TSAT > 20%) among HD patients initiating IV iron. Large prospective studies are needed to confirm these relationships.