Risk of Aspirin Use for Age-related Macular Degeneration

Abstract

BACKGROUND Age-related macular degeneration (AMD) is an eye disease that has been known to lead to blindness in aged people in most developed countries In some people AMD progresses slowly that vision loss does not occur for a long time On the other hand AMD causes sudden loss of central vision in one or both eyes Over time the blurred area might enlarge and blank spots will develop in the central vision Objects will not be as sharp or bright as they are used to be nAMD is one subtype of AMD which causes severe vision loss nAMD is resulted from abnormal growth of choroidal vessels which will lead to leakage of fluid or blood and swelling of macula and damage of vision The exact pathogenesis of nAMD is not clear yet One study found that there was deposition of complement membrane which attacks complex in choroidal endothelial cells and leads to macular degeneration in addition to cell apoptosis in nAMD patients That was similar to the pathogenesis of stroke and myocardial infarction (MI) Studies found that elderly Americans with nAMD had a higher risk of cardiovascular diseases compared with patients without nAMD which suggested that it might have common pathogenesis with cardiovascular diseases Various studies pointed out that prior onset of AMD might have higher risks for developing cardiovascular diseases such as MI Therefore we used NHIRD to examine the association of AMD and cardiovascular diseases Although the treatments for AMD nowadays are numerous none can cure the disease but only reserve current vision at most Therefore the risk factors for AMD or its impact on other diseases have drawn attention to prevent its occurrence Most well-known risk factors for AMD is aging smoking family history of AMD and Caucasian ethnicity Though the incidence of AMD is lower in Asians compared to Caucasians the effect of medications on AMD is still controversial for decades Aspirin is one of the medications mostly prescribed in patient with previous stroke or MI for secondary prevention Some aged people with high risks of cardiovascular events such as diabetes mellitus hypertension hyperlipidemia will be prescribed with aspirin for primary prevention as well However its side effects of increasing bleeding tendency such as gastrointestinal bleeding are highly concerned Therefore whether it will also induce bleeds in the abnormal vessels of AMD patients in those aged population is worth of investigation OBJECTIVE The study aimed to investigate (1) the association between AMD particularly the neovascular subtype and stroke myocardial infarction (MI) in Taiwan; (2) whether the longer time of aspirin use would increase the risk of AMD in post-MI patients; and (3) the impact of aspirin use on AMD compared to non-users MATERIALS AND METHODS We used the Taiwan National Health Insurance Research databases (NHIRD) for the following studies Firstly we constructed cohorts from 2001 to 2010 of newly-diagnosed neovascular AMD patients to explore its incidence of stroke and AMI Secondly we used total AMI patients’ database to conduct a nested case-control study from 2000 to 2008 to estimate the odds of aspirin users to non-aspirin uses Lastly we assembled cohorts from 2001 to 2013 to compare the risk of AMD between aspirin users and non-aspirin users In this study we used Cox multivariate regression model and propensity-score matching method to compare the risk of AMD RESULTS Firstly we had identified 931 cases in the nAMD group and 9 246 cases in the comparison group The incidence rate of all stroke events was estimated at 16 25 per 1 000 person-years and 11 42 per 1 000 person-years in the nAMD and matched groups (p

Date of Award	2018 May 31
Original language	English
Supervisor	Yea-Huei Kao (Supervisor)