In long-term users – heart attack survivors and people at high risk for one – discontinuation of low-dose aspirin in the absence of major surgery or bleeding was associated with a 37% increased risk of cardiovascular events.
For heart attack survivors and people at high risk for one, a low-dose aspirin is part of the daily routine to prevent a heart attack or stroke. But for those who don’t stick to that routine, the rate of heart attacks, strokes or deaths from one of those causes goes up 37%, a new study shows.
In broad patient settings, other research has shown up to 30% of patients stop taking aspirin, a drug that inhibits clotting and lowers the risk of cardiovascular events. The study examined the records of more than 600,000 people over age 40 who took low-dose aspirin for heart attack and stroke prevention between 2005 and 2009.
During three years of follow-up, there were 62,690 cardiovascular events. Researchers found that one in 74 patients who stopped taking aspirin had an additional cardiovascular event per year. The risk increased soon after stopping aspirin therapy and did not appear to diminish over time.
“Low-dose aspirin therapy is a simple and inexpensive treatment,” said Dr Johan Sundstrom, lead author of the study and professor of epidemiology at Uppsala University in Sweden.
Studies have suggested patients experience a “rebound effect” after stopping aspirin treatment, possibly due to increased clotting levels from the loss of aspirin’s blood-thinning effects. Because of the large number of patients on aspirin and the high number who stop treatment, the importance of a rebound effect may be significant, Sundstrom said.
“As long as there’s no bleeding or any major surgery scheduled, our research shows the significant public health benefits that can be gained when patients stay on aspirin therapy,” he said.
Background: There are increasing concerns about risks associated with aspirin discontinuation in the absence of major surgery or bleeding. We investigated whether long-term low-dose aspirin discontinuation and treatment gaps increase the risk of cardiovascular events.
Methods: We performed a cohort study of 601 527 users of low-dose aspirin for primary or secondary prevention in the Swedish prescription register between 2005 and 2009 who were >40 years of age, were free from previous cancer, and had ≥80% adherence during the first observed year of treatment. Cardiovascular events were identified with the Swedish inpatient and cause-of-death registers. The first 3 months after a major bleeding or surgical procedure were excluded from the time at risk.
Results: During a median of 3.0 years of follow-up, 62 690 cardiovascular events occurred. Patients who discontinued aspirin had a higher rate of cardiovascular events than those who continued (multivariable-adjusted hazard ratio, 1.37; 95% confidence interval, 1.34–1.41), corresponding to an additional cardiovascular event observed per year in 1 of every 74 patients who discontinue aspirin. The risk increased shortly after discontinuation and did not appear to diminish over time.
Conclusions: In long-term users, discontinuation of low-dose aspirin in the absence of major surgery or bleeding was associated with a >30% increased risk of cardiovascular events. Adherence to low-dose aspirin treatment in the absence of major surgery or bleeding is likely an important treatment goal.
Johan Sundström, Jakob Hedberg, Marcus Thuresson, Pernilla Aarskog, Kasper Munk Johannesen, Jonas Oldgren
[link url="https://news.heart.org/stopping-daily-aspirin-increases-heart-attack-stroke-risk/"]American Heart Association material[/link]
[link url="http://circ.ahajournals.org/content/136/13/1183.short?rss=1"]Circulation abstract[/link]