ASCEND: Aspirin, omega-3 supplements fail for primary prevention in diabetes
MUNICH — In a large cohort of patients with diabetes but no prior CVD, aspirin prevented vascular events but caused major bleeding events, and an omega-3 fatty acid supplement did not prevent vascular events, researchers from the ASCEND study reported at the European Society of Cardiology Congress.
The researchers randomly assigned 15,480 patients with diabetes and no CVD history (mean age, 63 years; 63% men) to receive aspirin 100 mg per day or placebo, and to receive 1 g per day of omega-3 fatty acids or olive oil placebo. Mean follow-up was 7.4 years. The findings were presented at the European Society of Cardiology Congress and published simultaneously in The New England Journal of Medicine.
During follow-up, the primary outcome of serious vascular events — defined as MI, ischemic stroke, transient ischemic attack or CV death excluding any intracranial hemorrhage — occurred in 8.5% of the aspirin group vs. 9.6% of the placebo group (rate ratio = 0.88; 95% CI, 0.79-0.97), according to data presented here.
However, major bleeding events — defined as intracranial hemorrhage, sight-threatening bleeding in the eye, gastrointestinal bleeding or other serious bleeding — were more common with aspirin treatment, at 4.1% in the aspirin group vs. 3.2% in the placebo group (rate ratio = 1.29; 95% CI, 1.09-1.52). According to the researchers, this finding was driven by GI bleeding and other extracranial bleeding.
“Aspirin did, as expected, reduce the risk of serious vascular events, but also, as expected, significantly increased the risk of major bleeding, by 29%,” Jane Armitage, FRCP, FFPH, from the Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population Health, University of Oxford, said in a press release. “And when we look at the balance of benefits vs. risks, the absolute benefit from avoiding serious adverse events were largely counterbalanced by the increased risk of bleeding. We were not able to identify any particular group for whom the benefits clearly outweigh the risks.”
GI tract cancer occurred in 2% of each group, while any cancer occurred at a similar rate (aspirin group 11.6%; placebo group, 11.5%).
“There was no suggestion that aspirin reduced the risk of cancer,” Armitage said during the press conference.
Fatty acid study
“ASCEND is the largest and longest-duration of omega-3 fatty acid supplements ever,” Louise Bowman, MD, from the Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population Health, University of Oxford, said in the press release. “In this study, we demonstrated no effect on the primary outcome of serious vascular events and no effect on cancer or total all-cause mortality.”
During the study period, the primary outcome of serious vascular events occurred in 8.9% of the fatty acid group vs. 9.2% of the placebo group (rate ratio = 0.97; 95% CI, 0.87-1.05), according to the researchers.
The key secondary outcome of first serious vascular event or any arterial revascularization occurred in 11.4% of the fatty acid group vs. 11.5% of the placebo group (rate ratio = 1; 95% CI, 0.91-1.09).
There was also no difference between the groups in all-cause death (fatty acid group, 9.7%; placebo group, 10.2%; rate ratio = 0.95; 95% CI, 0.86-1.05) or in nonfatal serious adverse events.
The adherence rate was 76%.
“Overall, our results suggest that current guideline recommendations should perhaps be reconsidered in terms of omega-3 fatty acid supplements,” Bowman said during the press conference.
The 1-g dose was chosen “based on earlier studies that showed promise of the 1-g dose,” she said. “It seemed the sensible approach, given that is what was being recommended. But the question does remain, would a higher dose have been effective?” – by Erik Swain
Armitage J, et al.
Bowman L, et al. Hot Line Session 2. Both presented at: European Society of Cardiology Congress; Aug. 25-29, 2018; Munich.
Disclosures: The study was supported in part by Abbott, Bayer, Mylan and Solvay. Armitage reports she has past or present research contracts with Bayer, Merck, Mylan and The Medicines Company. Bowman reports she received grants and/or nonfinancial support from Abbott, Bayer, Bayer Schering Pharma, Mylan and Solvay. Please see the study for a list of the other authors’ relevant financial disclosures.