Low-Dose Aspirin Discontinuation and Risk of Cardiovascular Events: A Swedish Nationwide, Population-Based Cohort Study

Circulation. 2017 Sep 26;136(13):1183-1192. doi: 10.1161/CIRCULATIONAHA.117.028321.


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.

Keywords: aspirin; cohort studies; primary prevention; secondary prevention.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Anti-Inflammatory Agents, Non-Steroidal / therapeutic use*
  • Aspirin / therapeutic use*
  • Cardiovascular Diseases / drug therapy*
  • Cardiovascular Diseases / epidemiology
  • Cardiovascular Diseases / pathology
  • Cardiovascular Diseases / prevention & control*
  • Cohort Studies
  • Female
  • Follow-Up Studies
  • Humans
  • Incidence
  • Male
  • Medication Adherence
  • Middle Aged
  • Proportional Hazards Models
  • Risk
  • Sweden / epidemiology


  • Anti-Inflammatory Agents, Non-Steroidal
  • Aspirin