Abstract
Purpose :
Anemia may play a role in vascular changes implicated in open angle glaucoma (OAG) and normal tension glaucoma (NTG). We posit that blood transfusion-induced hypervolemia and subsequent red blood cell dilution causes reduced perfusion to the optic nerve, which contributes to the development of OAG and NTG. The purpose of this study was to explore the association between blood transfusion-related anemia and glaucoma.
Methods :
This cross-sectional study examined all US California (CA) Medicare beneficiaries from the 2015 part B carrier claims databases obtained from the Centers for Medicare & Medicaid Services. The inclusion criteria were those who lived in CA in 2015, were 65 years or older, had Medicare part A and part B coverages, and had at least one part B claim in 2015. The outcomes of interest were OAG and NTG and the exposures of interest were all-cause anemia and blood transfusion-related anemia, defined by the occurrence of corresponding International Classification of Diseases, Ninth or Tenth Revision diagnosis codes. Potential confounders included age, sex, race/ethnicity, and Charlson Comorbidity Index scores. The association between anemia and glaucoma was assessed using logistic regression models, adjusting for all potential confounders described above.
Results :
Among 2,574,641 CA Medicare patients, the overall prevalence of OAG and NTG was 5.9% (152,459) and 0.38% (9,862), respectively. After excluding patients with other types of glaucoma, CA Medicare patients had increased odds of OAG if they had all-cause anemia (adjusted OR=1.10; 95% CI:1.08, 1.11) compared with those without any anemia, and increased odds of OAG if they had transfusion-related anemia (adjusted OR=1.07; 95% CI:1.05, 1.10) compared with those without transfusion-related anemia. After further excluding those with other types of OAG, there was some evidence of increased odds of NTG for those with all-cause anemia (adjusted OR=1.05; 95% CI:1.00, 1.11) and those with transfusion-related anemia (OR=1.09; 95% CI:1.00, 1.19).
Conclusions :
Our study identified a statistically significant association between anemia and OAG in the CA Medicare population. The association between anemia and NTG may be less pronounced, which could be secondary to practitioners under-coding NTG in the CA Medicare population. These findings indicate the need for further studies to analyze the impact of anemia on glaucoma, especially NTG.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.