Association between Ischemic Stroke and Iron-Deficiency Anemia: A Population-Based Study

Background: Very little is known about the relationship between non-sickle cell anemia and stroke. The purpose of this study is to evaluate the association of iron-deficiency anemia (IDA) with stroke based on a nationwide coverage database in Taiwan. Methods: The case-control study subjects were obtained from the Taiwanese Longitudinal Health Insurance Database 2000. We included 51,093 subjects with stroke as cases and randomly selected 153,279 controls (3 controls per case) in this study. Separate conditional logistic regression analyses were used to calculate the odds ratio (OR) for having been previously diagnosed with IDA between cases and controls. We further analyzed the association between stroke and IDA by stroke subtype. Results: Results showed that 3,685 study subjects (1.81%) had been diagnosed with IDA prior to the index date; of those subjects, 1,268 (2.48%) were cases and 2,417 (1.58%) were controls (p<0.001). Conditional logistic regression shows that the OR of having previously received an IDA diagnosis among cases was 1.49 (95% CI: 1.39+/-1.60; p<0.01) that of controls after adjusting for monthly income, geographic region, hypertension, diabetes, coronary heart disease, atrial fibrillation, heart failure, hyperlipidemia, tobacco use disorder, and alcohol abuse/alcohol dependency syndrome. Furthermore, the adjusted OR of prior IDA for cases with ischemic stroke was found to be 1.45 (95% CI: 1.34 similar to 1.58) compared to controls. However, we did not find any significant relationship between IDA and subarachnoid/intracerebral hemorrhage even adjusting for other confounding factors (OR=1.17, 95% CI=0.97 similar to 1.40). Conclusion: There is a significant association between prior IDA and ischemic stroke.