Retrospective study of the association between transfusion frequency and potential complications of iron overload in patients with myelodysplastic syndrome and other acquired hematopoietic disorders.

Background: Patients with myelodysplastic syndrome (MDS) and other acquired hematopoietic disorders frequently require chronic transfusion therapy. Although red cell transfusions are known to cause iron overload, data on the risk of iron-related complications in these patients are limited.

Methods: This was a retrospective, case-control study to assess the association between exposure to transfusions and complications of iron overload in patients with MDS and other hematopoietic disorders using a large US health-insurance claims database spanning 1997-2004. Subjects included members with one or more claims with a diagnosis of 'neoplasm of uncertain behavior of other lymphatic and hematopoietic tissues' (ICD-9-CM 238.7) and no claims for potential complications of iron overload (cardiomyopathy/heart failure, conduction/rhythm disorders, diabetes, liver disease) prior to the diagnosis date. Cases were defined as subjects with claims for complications of iron overload after the diagnosis date and were compared with a corresponding number of controls (patients without complications) with respect to receipt of transfusions, controlling for demographic and clinical characteristics using multivariate conditional logistic regression.

Results: A total of 4546 patients met inclusion criteria including 511 cases and a corresponding number of controls. Receipt of transfusions was significantly associated with risk of potential complications of iron overload (odds ratio [OR] = 2.90; p = 0.0008). Results for specific potential complications were as follows: cardiomyopathy/heart failure (OR = 1.62; p = 0.2955), conduction/rhythm disorders (OR = 4.18; p = 0.0005), diabetes (OR = 5.06; p = 0.0025), and liver disease (OR = 3.31; p = 0.0008).

Conclusion: These results suggest that transfusion therapy may increase risk of complications of iron overload in patients with MDS or other hematopoietic disorders. Further research is needed to assess whether the associations observed in this retrospective observational study are due to iron overload or other factors.