Black patients with diagnosed and treated glaucoma and those with high pressure in their eyes appear to have an increased risk of death from cardiovascular causes, according to a new report.
"Glaucoma is one of the leading causes of visual impairment worldwide," the authors write as background information in the article. "The most common type, primary open-angle glaucoma, is especially prevalent in populations of African origin, in which it is the foremost cause of blindness." In addition to higher rates of open-angle glaucoma, black populations also tend to have higher rates of death from chronic disease and high pressure within their eyes (ocular hypertension) than white populations.
Suh-Yuh Wu, M.A., of Stony Brook University, Stony Brook, New York, and colleagues studied 4,092 participants age 40 to 84 (average age 58.6) in the Barbados Eye Studies, which assess a predominately black population with similar ancestry to African-Americans. Initial visits occurred between 1987 and 1992. Height, weight and blood pressure were recorded; interviews were conducted; and various eye measurements were taken. These included photographs of the retina and measurements of eye pressure.
At the beginning of the study, 300 participants had glaucoma, including 141 who had been diagnosed and treated. After nine years of follow-up, 764 (19 percent) of the participants had died. After adjusting for other factors, glaucoma was not associated with the risk of death overall. However, the risk of death from cardiovascular causes was 38 percent higher in individuals who had previously been diagnosed with or treated for open-angle glaucoma and 91 percent higher in those who had been treated with one particular agent, the beta-blocker timolol maleate. Cardiovascular deaths were also 28 percent higher in those with ocular hypertension at the beginning of the study.
"One explanation for the excess mortality [death] found in persons with previously diagnosed open-angle glaucoma could be their longer duration of disease compared with those with newly diagnosed disease," the authors write. "Another explanation for an increased mortality risk could be related to the open-angle glaucoma treatment received." Adverse effects or inappropriate use of beta-blockers and other medications used to treat glaucoma may harm the cardiovascular system and increase death risk.
Some evidence suggests that risk factors for ocular hypertension and cardiovascular disease are similar, potentially explaining the increased risk of death associated with ocular hypertension, the authors note. "These findings underscore the importance of close monitoring and controlling of adequate intraocular pressure levels in this and other high-risk populations," they conclude.
Journal reference: Arch Ophthalmol. 2008;126:365-370.
This study was supported by grants from the National Eye Institute, Bethesda, Md.
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