Abstract
Purpose: :
To investigate the association between neovascular AMD and the development of MI among elderly Americans.
Methods: :
We obtained a 5% sample of Medicare beneficiaries and their medical reimbursement claims from 2000–2003. A total of 1,519,806 beneficiaries from this sample during the first two years formed a cohort of persons aged >65 years. We extracted baseline demographic data and defined baseline conditions (neovascular AMD, MI, hypertension, and diabetes) from the Medicare data based on relevant ICD–9 codes on at least one claim’s "Claim Principal Diagnosis Code" field during the 2–year baseline period (2000–2001). After excluding 73,409 persons with a history of MI at baseline, we used 2002–2003 claims data to identify incident MI cases (n=56,541) among 1,446,397 persons without a history of MI at baseline.
Results: :
At baseline, the mean age of this cohort was 76 years, and included 60% women and 88% Caucasians; 11% of beneficiaries had been diagnosed with AMD, of which 19% was the neovascular form. Baseline age–, gender–, and race–adjusted prevalence of hypertension, diabetes, and MI were 73%, 28%, and 4.7%, respectively, among persons with neovascular AMD, in contrast to 65%, 25%, and 4.5% among persons without neovascular AMD (p <0.01 for all three conditions). After adjusting for age, gender, race, hypertension, and diabetes, the 2–year incident odds ratios (and 95% confidence intervals) of MI associated with neovascular AMD were 1.10 (1.00, 1.21), 1.11 (1.04, 1.19), 1.17 (1.11, 1.23), and 1.23 (1.18, 1.27) for persons aged 65–69, 70–74, 75–79, and >80 years, respectively.
Conclusions: :
Cross–sectionally, neovascular AMD is associated with hypertension, diabetes, and a history of MI independent of age, gender, and race. Further, the presence of neovascular AMD is associated with a higher risk of incident MI, independent of demographic factors and comorbidity. This finding, if confirmed by other studies with the ability to control for smoking and other lifestyle factors, suggests the possibility of shared common antecedents of these two diseases.