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Statins, aspirin therapy help prevent progression from dry to wet AMD
Study finds that patients with CNV and AMD were less likely to take statins or aspirin and more likely to smoke.
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The progression of dry age-related macular degeneration to the more severe wet form of the disease may be reduced through the therapeutic use of cholesterol-lowering statins and aspirin, a recent study suggests.
First author Hilary L. Wilson, MD, and colleagues at the University of California San Francisco School of Medicine and the San Francisco Veterans Affairs Hospital Eye Clinic investigated the association between statins and choroidal neovascularization among patients with AMD.
Statins are a group of lipid-lowering medications used to reduce serum cholesterol levels in patients with cardiovascular disease, heart disease, diabetes, stroke and other medical conditions. Statins are the largest selling class of drugs in the world, according to pharmaceutical market analysts IMS Health.
Dr. Wilson and colleagues noted that previous work has suggested associations between statins and the risk of AMD.
“Preliminary evidence suggests that cholesterol-lowering medications may be associated with a reduced risk of progression of age-related maculopathy and that statins may be associated with a reduced risk of AMD,” the study authors said in an article in American Journal of Ophthalmology.
Choroidal neovascularization, the vision-threatening component of wet AMD, has been associated by previous researchers with elevated serum cholesterol and inflammation in Bruch’s membrane, the researchers said.
“We looked retrospectively at people with AMD who had taken statins for other reasons,” said Jacque L. Duncan, MD, the senior author of the study, in an e-mail to Ocular Surgery News. “We then checked the medical record to see at what age (if any) they developed CNV. We found that those who had taken statins developed CNV at lower rates compared to AMD patients who had not taken statins.”
Study methods
Researchers conducted a retrospective chart review of fundus photographs and fluorescein angiographs of patients with AMD from the San Francisco Veterans Affairs Hospital Eye Clinic. Patients were seen between January 1990 and March 2003.
Photography files of 326 AMD patients were reviewed by a retinal specialist. Patient files were classified as having dry AMD with at least five soft drusen with or without retinal pigment epithelial abnormalities in the macula of each eye; dry AMD with geographic atrophy (GA) with retinal depigmentation 175 µm in diameter, sharp edges and visible choroidal vessels; or CNV AMD with drusen and/or retinal pigment epithelial changes in at least one eye. According to the study authors, CNV was evidenced on angiograms by subretinal macular hemorrhages, lipid deposits in the macula, fibrotic macular scarring and/or retinal pigment epithelial detachment.
Medical records of patients were reviewed to determine possible risk factors for CNV and additional medical conditions that might predispose patients toward statin use (eg, high cholesterol and triglycerides, fasting blood glucose, family history of coronary heart disease).
Patients were excluded from the study if CNV was secondary to a disease other than AMD, AMD was not present upon review of the fundus photos, medical files were incomplete or patients were not adequately followed, patients were on statins for less than 6 months or patients were younger than 60 years.
Patient profiles
One hundred four patients with CNV, 204 patients with dry AMD and 18 patients with dry AMD and GA were included in study outcome data. Researchers found that patients with CNV had similar backgrounds and medical profiles as patients with dry AMD.
The median age for patients with CNV was 75 years, 77 years for patients with dry AMD and 78 years for patients with dry AMD and GA. Ninety-five percent of CNV patients, 95% of dry AMD patients and 94% of dry AMD with GA patients were men.
“The majority of subjects in each group were white. Subjects were also similar with respect to a number of medical variables, as well as baseline total low-density lipoprotein cholesterol levels and all follow-up serum lipid profiles among statin users,” the authors said.
Statins, smoking, aspirin
Patients with CNV were less likely than patients with dry AMD with or without GA to have taken statins for at least a 6-month period. Twenty percent of patients with CNV were treated with statins as compared to 38% and 33% of patients with dry AMD without or with GA, respectively. This difference was statistically significant (P = .011).
“Subjects with CNV were significantly less likely to use statins or aspirin than subjects with dry AMD,” the authors reported. “In addition, subjects with CNV were significantly more likely to have higher serum triglyceride levels and lower serum DHL cholesterol levels and more likely to be current smokers.” Smoking was common among patients with CNV at “nearly twice the rate” as compared to patients who had dry AMD without GA (P = .013).
Patients with CNV were also less likely to use aspirin than patients with dry AMD. According to study authors, 60% of patients with CNV were treated with aspirin, compared with 75% and 67% of patients with dry AMD without or with GA, respectively. This was statistically significant (P = .0003).
Probability of progression
To judge the probability of patients with dry AMD progressing to wet AMD, researchers utilized a multipredictor model, which compared at-risk dry AMD patients to dry AMD patients who used statins and aspirin. For the analysis, researchers assumed all at-risk dry AMD patients were smokers who did not take aspirin and had moderately high triglyceride levels.
“The probability of CNV ranges from 0.07 higher at age 60 to 0.24 higher at age 82 for the nonstatin group, and the median time to CNV is about 8 years earlier [age 75 vs. age 83] in the group not on statins,” the researchers said.
Based on the data accumulated in the study, researchers said that serum triglycerides and HDL cholesterol levels at baseline are significantly related to AMD status.
“In conjunction with the increased risk of CNV found among current smokers and patients with elevated serum triglycerides and low serum HDL cholesterol levels, the present study provides evidence to support the hypothesis that a common disease mechanism is responsible for both cardiovascular disease and advanced AMD,” the researchers concluded.
For Your Information:Reference:
- Jacque L. Duncan, MD, is an assistant professor of ophthalmology at University of California, San Francisco, and senior author of the study. She can be reached at Department of Ophthalmology, University of California, San Francisco, 10 Koret Way, #K129, San Francisco, CA 94143; 415-514-4241; fax: 415-476-0336; e-mail: jduncan@itsa.ucsf.edu.
- Wilson HL, Schwartz DM, Bhatt HRF, et al. Statin and aspirin therapy are associated with decreased rates of choroidal neovascularization among patients with age-related macular degeneration. Am J Ophthalmol. 2004;137(4):615-624.
- OSN Staff Writer Nicole Nader covers pediatrics and strabismus and neuro-ophthalmology, in addition to cataract and refractive surgery.