Awareness of and Identifying Iron Overload in Transfusion-Dependent Patients Can Be Improved: A Retrospective Review At a Single Tertiary Care Centre

Several patient populations, including those with thalassemia, sickle cell disease, and bone marrow failure syndromes, often require red blood cell (RBC) transfusions and are at risk of iron overload. Chronic RBC transfusions lead to an increase in morbidity and mortality, particularly as a result of iron overload, proven in patients with thalassemia major and implicated in certain bone marrow failure syndromes such as myelodysplasia. Guidelines currently recommend iron chelation in these various clinical settings, yet the true incidence of iron overload and physician awareness patterns remain unknown. Iron overload is likely under recognized and under managed. We aim to determine the incidence of iron overload in transfusion-dependent patients in a general tertiary care centre and to determine if physicians are adequately screening for and considering treatment for iron overload.

All adult patients at a single tertiary care centre, London Health Sciences Centre (LHSC), who received at least one RBC transfusion between January 1, 2006 and December 31, 2008, were captured through the local Blood Transfusion Laboratory (BTL) database. Patients who were deemed transfusion-dependent, defined as having received a minimum of 12 units of RBCs in any 12 month period with at least one RBC transfusion every 8 weeks, were identified for further analysis. This was based on the World Health Organization (WHO) criteria for RBC transfusion dependency in patients with myelodysplastic syndrome (MDS), where RBC transfusion dependency was defined as having at least one RBC transfusion every 8 weeks over a period of 4 months. Full chart reviews for these patients from the beginning of the study period to up to 12 months after the last transfusion in the LHSC BTL database during the study period were performed. For these transfusion-dependent patients, the number who had ferritin levels checked was determined. Those who had a ferritin level >1000μg/L were considered to have iron overload. Finally, of these patients who were transfusion-dependent with iron overload, full chart reviews during the study period were undertaken to determine if treating physicians considered monitoring for and treating the iron overload.

The LHSC BTL database included a total of 67449 RBC transfusions administered to 12486 unique patients during the study period. 1200 patients (6.6%) received at least 12 units of RBCs during the study period and were evaluated further. 48 adult patients (0.4%) satisfied the criteria for RBC transfusion dependence.

Of the 48 transfusion-dependent patients, 40 (83.3%) had a ferritin value measured during and/or up to 12 months following the end of the study period. 30 (75.0%) transfusion-dependent patients with a ferritin measurement were deemed to have iron overload, consisting of patients with MDS (n=13), myelofibrosis (n=4), beta thalassemia (n=3), red cell aplasia (n=3), aplastic anemia (n=1), and other diagnoses (n=6). In this smaller cohort of 30 patients, 24 patients (80.0%) had physicians that referred to the possibility of iron overload in the clinical notes and only 16 patients (53.3%) were treated with iron chelation at some point during the study period.

In a general tertiary care centre the percentage of transfusion-dependent patients is low compared to the total number of patients who are transfused. The percentage of transfusion-dependent patients who treating physicians monitored for or identified iron overload and subsequently managed were slightly higher than previous published rates. However, awareness of and identifying iron overload in transfusion-dependent patients at a general tertiary care centre can be improved.

Hugel:Novartis: Unspecified Educational Fund.