Increased iron requirement in hemodialysis patients on antiplatelet agents or warfarin

Many hemodialysis patients receive antiplatelet therapy or warfarin; however, little is known about the effect of this on iron requirements. Given the association of antiplatelet therapy with bleeding we hypothesized that there should be a greater need for iron in such patients, which we tested in this study.

Retrospective 1-year cohort study of 205 chronic hemodialysis patients. The primary outcome variable was total iron dose, which was analyzed according to antiplatelet/warfarin use. Data were also collected on potential confounders, allowing for both unadjusted and adjusted (multiple regression) analysis.

97/205 patients received antiplatelet/warfarin therapy. This group was older, with a higher incidence of macrovascular disease and diabetes and a higher median C-reactive protein (6.0 vs. 3.75 mg/l). Overall, median iron requirement was 1,300 mg/year. In a multiple regression analysis, antiplatelet/warfarin use was associated with an additional iron requirement of 703 mg (95% confidence interval 188-1,220 mg), with the strongest effect observed in patients with normal inflammatory markers.

We found a high requirement for iron in patients receiving antiplatelet agents/warfarin. We argue that the most likely mechanism for this association is chronic, low-grade blood loss, although further study is required before causality can be established.