During a mean (SD) follow-up of 6.0 (2.1) years involving over 100 000 participants [...] There was no significant reduction in CVD death (OR, 0.99; 95% CI, 0.85-1.15) or cancer mortality (OR, 0.93; 95% CI, 0.84-1.03)
I am suspicious of the 6-year followup. In the original paper linked elsewhere in this comment tree, the observed reduction in cancer mortality grew over time.
I would be more willing to believe this new study if it followed patients for a longer period of time, observed the reduction in cancer mortality, and still concluded that the risks outweighed the benefits.
I’d like to point out that this pooled analysis of healthy people covered more than 4 times as many healthy people as your original citation covered sick people.
Do you think that the “sick people” were somehow susceptible to cancer in an aspirin-prevention-friendly manner, while the “healthy people” weren’t?
(I am considering cancer separately from cardiovascular disease and bleeding risks, as they can be analyzed separately before overall risk-benefit is determined. I would not be surprised to learn that aspirin is very effective at reducing cardiovascular disease among those at risk, while not being worth it for cardiovascular disease among the general population.)
I’ll try again: your original cite said the cancer benefit was detectable at 5 years, and later. I’ve presented you with a 4 times larger study, in the relevant subpopulation, at 6 years which found no cancer benefit—and you are still asking rhetorical questions and coming up with excuses.
Do you think that if you had seen the evidence the other way around that you would be asking the same questions?
No matter which study I saw first, the other would be surprising. A 100k trial doesn’t explain away evidence from eight trials totaling 25k. Given that all of these studies are quite large, I’m more concerned about methodological flaws than size.
I have very slightly increased my estimate that aspirin reduces cancer mortality (since the new study showed 7% reduction, and that certainly isn’t evidence against mortality reduction). I have slightly decreased my estimate that the mortality reduction is as strong as concluded by the meta-analysis. I have decreased my estimate that the risk tradeoff will be worth it later in life. I have very slightly increased my estimate that sick people are generally more likely to develop cancer and aspirin is especially good at preventing that kind of cancer, but I mention that only because it’s an amusingly weird explanation.
If this new study is continued with similar results, or even if its data doesn’t show increased reduction when sliced by quartile (4.6, 6.0, 7.4 years), I would significantly lower my estimate of the mortality reduction.
I’ll continue to take low-dose aspirin since my present risk of bleeding death is very low, and if the graphs of cumulative cancer mortality reduction on p34 of the meta-analysis reflect reality, I’ll be banking resistance to cancer toward a time when I’m much more likely to need it. I can’t decide to take low-dose aspirin retroactively.
Perhaps I’m misunderstanding the numbers (“OR, 0.93”), but the new study observed a 7% decrease in cancer mortality, which they called “not significant”.
Do you think that if you had seen the evidence the other way around that you would be asking the same questions?
I would be unhappy with the other study’s population, but very happy with its followup period. (The fact that the observed benefit grew with the length of time taking aspirin was especially convincing, as I mentioned earlier. That is a property that is very unlike “maybe we’re seeing it, maybe we’re not” noise at the threshold of detection.)
Last year, I told you that polio had no natural reservoirs, and you continued to believe otherwise, so I am not especially inclined to argue further.
Perhaps I’m misunderstanding the numbers (“OR, 0.93”), but the new study observed a 7% decrease in cancer mortality, which they called “not significant”.
No, that’s correct. If you want to use stuff that doesn’t reach significance, I can’t stop you. (You didn’t reply to Yvain’s points, incidentally.)
Last year, I told you that polio had no natural reservoirs, and you continued to believe otherwise, so I am not especially inclined to argue further.
And you misunderstood the point about carriers defeating eradication attempts.
From the abstract at:
http://archinte.ama-assn.org/cgi/content/abstract/archinternmed.2011.628v1
I am suspicious of the 6-year followup. In the original paper linked elsewhere in this comment tree, the observed reduction in cancer mortality grew over time.
I would be more willing to believe this new study if it followed patients for a longer period of time, observed the reduction in cancer mortality, and still concluded that the risks outweighed the benefits.
I’d like to point out that this pooled analysis of healthy people covered more than 4 times as many healthy people as your original citation covered sick people.
Do you think that the “sick people” were somehow susceptible to cancer in an aspirin-prevention-friendly manner, while the “healthy people” weren’t?
(I am considering cancer separately from cardiovascular disease and bleeding risks, as they can be analyzed separately before overall risk-benefit is determined. I would not be surprised to learn that aspirin is very effective at reducing cardiovascular disease among those at risk, while not being worth it for cardiovascular disease among the general population.)
I’ll try again: your original cite said the cancer benefit was detectable at 5 years, and later. I’ve presented you with a 4 times larger study, in the relevant subpopulation, at 6 years which found no cancer benefit—and you are still asking rhetorical questions and coming up with excuses.
Do you think that if you had seen the evidence the other way around that you would be asking the same questions?
No matter which study I saw first, the other would be surprising. A 100k trial doesn’t explain away evidence from eight trials totaling 25k. Given that all of these studies are quite large, I’m more concerned about methodological flaws than size.
I have very slightly increased my estimate that aspirin reduces cancer mortality (since the new study showed 7% reduction, and that certainly isn’t evidence against mortality reduction). I have slightly decreased my estimate that the mortality reduction is as strong as concluded by the meta-analysis. I have decreased my estimate that the risk tradeoff will be worth it later in life. I have very slightly increased my estimate that sick people are generally more likely to develop cancer and aspirin is especially good at preventing that kind of cancer, but I mention that only because it’s an amusingly weird explanation.
If this new study is continued with similar results, or even if its data doesn’t show increased reduction when sliced by quartile (4.6, 6.0, 7.4 years), I would significantly lower my estimate of the mortality reduction.
I’ll continue to take low-dose aspirin since my present risk of bleeding death is very low, and if the graphs of cumulative cancer mortality reduction on p34 of the meta-analysis reflect reality, I’ll be banking resistance to cancer toward a time when I’m much more likely to need it. I can’t decide to take low-dose aspirin retroactively.
It doesn’t have to, since they are not trials involving the same populations.
Perhaps I’m misunderstanding the numbers (“OR, 0.93”), but the new study observed a 7% decrease in cancer mortality, which they called “not significant”.
I would be unhappy with the other study’s population, but very happy with its followup period. (The fact that the observed benefit grew with the length of time taking aspirin was especially convincing, as I mentioned earlier. That is a property that is very unlike “maybe we’re seeing it, maybe we’re not” noise at the threshold of detection.)
Last year, I told you that polio had no natural reservoirs, and you continued to believe otherwise, so I am not especially inclined to argue further.
No, that’s correct. If you want to use stuff that doesn’t reach significance, I can’t stop you. (You didn’t reply to Yvain’s points, incidentally.)
And you misunderstood the point about carriers defeating eradication attempts.