Reduced aspirin use linked to lower bleeding risk among patients on warfarin
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An aspirin de-implementation intervention appeared associated with reduced bleeding risk patients hospitalized with atrial fibrillation and/or venous thromboembolism and taking warfarin, according to data published in JAMA Network Open.
Researchers observed a 32.3% decrease in risk for major bleeds among the overall cohort during the study intervention.
Background
“We previously looked at our multicenter data and saw that among patients on warfarin who did not have a clear indication for aspirin, those who received aspirin had a higher rate of bleeding and complications than similar patients not taking aspirin,” Geoffrey D. Barnes, MD, MSc, cardiologist at University of Michigan Health Frankel Cardiovascular Center, told Healio. “We wanted to see if we could systematically reduce unnecessary aspirin use and reduce bleeding risk.”
The observational study included 6,738 patients (mean age, 62.8 years; 53.1% women) who received care across a six-center quality improvement collaborative in Michigan between 2010 and 2019. Patients received warfarin for atrial fibrillation and/or VTE without an apparent indication for concomitant aspirin use.
As part of the intervention, researchers asked primary care physicians of aspirin users whether an indication existed for an ongoing combination of aspirin and warfarin. Aspirin was discontinued with the approval of the treating physician among patients for whom it was not indicated.
Researchers assessed the rate of aspirin use, bleeding and thrombotic outcomes before and after the intervention, as well as before and after 24 months before the intervention, when decreases in aspirin use rates began. They additionally used an interrupted time series analysis to assess cumulative monthly event rates throughout time.
Median follow-up was 6.7 months (interquartile range, 3.2-19.3).
Results
Overall aspirin use decreased from 29.4% (95% CI, 28.9-29.9) at baseline to 27.1% (95% CI, 26.1-28) during the 24 months before the intervention (P < .001), with an accelerated decrease in mean aspirin use after the intervention to 15.7% (95% CI, 14.8-16.8).
Results showed an association of reduced aspirin use with lower risk for major bleeding events per month, from 0.31% (95% CI, 0.27-0.34) before the intervention to 0.21% (95% CI, 0.14-0.28) after the intervention. However, researchers observed no significant change in mean percentage of thrombotic events (0.21% vs. 0.24%).
Moreover, reduced aspirin use starting 24 months before the intervention appeared associated with decreases in mean percentage for any bleeding event (2.3% vs. 1.5%; P = .02 for change in slope before and after 24 months before the intervention), a major bleeding event (0.31% vs. 0.25%; P = .001 for change in slope) and an ED visit for bleeding (0.99% vs. 0.67%; P = .04 for change in slope).
Researchers did not observe mean percentage changes in thrombotic events.
Implications
“The findings indicate the need for physicians to review patient medication lists to determine if aspirin can be safely de-prescribed, especially if the patient is also taking a chronic anticoagulant,” Barnes said.
Health systems should also consider investing in antithrombotic stewardship programs that allow for population-based screening for unnecessary aspirin use and assist with de-prescribing, he added.
“We will continue to see how long this systematic intervention within the anticoagulation clinics is sustained,” Barnes said. “We also are exploring ways to initiate similar systematic identification and de-prescribing among patients on chronic direct oral anticoagulant [DOAC] therapy. This is important since most DOAC-treated patients are not followed in structured anticoagulation clinics.”
For more information:
Geoffrey D. Barnes, MD, MSc, can be reached at Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, 2800 Plymouth Road, Bldg 14 G214, Ann Arbor, MI 48109; email: gbarnes@umich.edu.
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