The news reports today included some work from the Blue Mountains Eye Study recently released which concluded:
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Conclusion Regular aspirin use is associated with increased risk of incident neovascular AMD, independent of a history of cardiovascular disease and smoking.
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This comes from:

http://archinte.jamanetwork.com/article.aspx?articleid=1558450#qundefined

I think I need someone more up to date with assessing studies like this, because my immediate response was, yes, the people taking aspirin would be the people with poor vascular systems anyway, because it is used to mitigate stroke risk. So I would expect them to have a greater risk of vascular retinal problems too, as the retinal vasculature is very fine and is affected by general vascular disease the same as the rest of the body. I think they have controlled for cardiovascular disease, but I’m not quite sure.

I think what I am saying is that those taking aspirin are more likely to have disease anyway and those not taking aspirin possibly don’t.

I think I am confusing myself.

buffy said:

The news reports today included some work from the Blue Mountains Eye Study recently released which concluded:
————-
Conclusion Regular aspirin use is associated with increased risk of incident neovascular AMD, independent of a history of cardiovascular disease and smoking.
————-

This comes from:

http://archinte.jamanetwork.com/article.aspx?articleid=1558450#qundefined

I think I need someone more up to date with assessing studies like this, because my immediate response was, yes, the people taking aspirin would be the people with poor vascular systems anyway, because it is used to mitigate stroke risk. So I would expect them to have a greater risk of vascular retinal problems too, as the retinal vasculature is very fine and is affected by general vascular disease the same as the rest of the body. I think they have controlled for cardiovascular disease, but I’m not quite sure.

I think what I am saying is that those taking aspirin are more likely to have disease anyway and those not taking aspirin possibly don’t.

I think I am confusing myself.

how come its taken them all this time to find this out

anecdotally doctors would have worked this one out years ago

Oh, for those not in my field…..current theory for vascular macular degeneration is that the fine vessels near the macula (the macula itself is avascular) fail to deliver, so the body goes “hey, retina can’t breathe, isn’t getting fed….quick, make more blood vessels”.. These neovascular nets are very fragile and prone to leakage. This is not a Good Thing. The injections used in treatment are anti-VEGF, which means anti vascular endothelial growth factor, the chemical signal to make more blood vessels.

Yep, aspirin users were: older, more likely to have had a stroke, diabetes, and to have hypertension. They didn’t take into account aspirin dose.

It was only at 10 and 15 years that the difference was significant. so the participants on ave would have been 75 or 80.

Didn’t look at family history of AMD.

In absolute risk terms, non users have a risk of 0.5% aspirin users have a risk of 1% of developing neovascular AMD.

Thank you poikilotherm. It felt dodgy, but the Blue Mountains study is supposed to be a world class one. And I couldn’t quite put my finger on what felt wrong.

Can you remember the name of the thing you have to account for by which in older populations the more sickly have already popped off so you are only really looking at the fitter population anyway? I once knew what it was called and it’s got lost in the mists of time. It’s particularly relevent to AMD, because it affects older people. (Don’t believe the ads….I’ve never seen it in people in their 50s, rarely in their 60s. And 20% of my patients are 80 or older and it’s certainly not rampant. Although, far more people are actually being treated for it than I suspect is appropriate. And the treatment protocols are somewhat jumbled)

I’m not sure. Although, they did use a Kaplan Meier estimation, which takes that kind of thing into account. Only caveat is they need to have a large enough sample population. I’m not sure ~280 aspirin users was large enough (~2500 controls).

heh…marginally…why use a cut off then (plus the CI includes 1 – suggesting in some it was mildly protective of AMD…)

“ We note that, after adjustment for additional CVD risk factors (BMI, blood pressure, blood total cholesterol level, diabetes mellitus, fish consumption, inflammatory markers), our findings became marginally nonsignificant (OR, 2.05; 95% CI, 0.96-4.40; P = .06)”

I still haven’t found the exact thing I was looking for, but this paper is an interesting summary of how to read stats in medical papers:

http://onlinelibrary.wiley.com/doi/10.1111/j.1444-0938.2006.00030.x/abstract

From that paper I linked, this might actually be what I was trying to remember:

“An example of this bias could be the apparent protective effect of smoking on the development of age related maculopathy. The reason that smokers are under-represented in patientw with ARM is more likely to be that they die earlier and as a result do not live long enough to develop this age-related disease.”