Abstract
Purpose :
To evaluate the association between oral iron supplementation and retinal or subretinal hemorrhage in participants with neovascular age-related macular degeneration (AMD) in the Comparison of AMD Treatments Trials (CATT).
Methods :
At baseline, CATT participants were interviewed for use of oral iron supplements. Trained readers evaluated baseline fundus photographs for the presence and size of retinal/subretinal hemorrhage. The associations between any iron supplement use (yes/no), iron dosage (no use, <18mg [typical iron dose in multivitamins], 18-36 mg, >36 mg) and hemorrhage at baseline were analyzed among all participants, participants without past history or ongoing anemia, and stratified by hypertension status and number of risk alleles for complement factor H (CFH). Multivariate logistic regression models were used to adjust for age, gender, smoking status, anemia status, dietary supplement use, diabetes, hypertension, cardiovascular diseases, use of antiplatelet or anticoagulant, and neovascular AMD in the fellow eye.
Results :
Among 1165 participants with gradable photographs, baseline retinal/subretinal hemorrhage was present in the study eye in 71% of 181 iron users and in 61% of 984 participants without iron use (adjusted OR=1.45, 95% CI, 1.01-2.09, p=0.04), and the association was dose-dependent (65% for <18mg, 70% for 18-36 mg, 76% for >36 mg, adjusted linear trend p=0.048, Table 1).
Among participants with hypertension at baseline (n=802), the association of iron use with hemorrhage was significant (adjusted OR=1.87, p=0.006) but was not significant among those without hypertension at baseline (OR=0.87, p=0.68, Table 1). The association of iron use with hemorrhage was also significant among hypertensive participants without anemia (n=698) (adjusted OR=1.85, p=0.02, Table 2). In the 835 participants who were genotyped, the OR for the association of iron use with hemorrhage increased from 1.28 for participants with 0 risk allele to 2.17 for participants with two risk alleles of CFH (interaction p=0.21).
Conclusions :
Among CATT participants, use of oral iron supplements was significantly associated with retinal/subretinal hemorrhage in a dose-response manner. This association was stronger in participants with hypertension. The association with CFH warrants further investigation.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.