Increased risk of stroke after discontinuation of acetylsalicylic acid: A UK primary care study

• Published in: Neurology Vol. 76; no. 8; pp. 740 - 746
• Main Authors: GARCIA RODRIGUEZ, Luis A, CEA SORIANO, Lucía, HILL, Catherine, JOHANSSON, Saga
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 22-02-2011
• Subjects: Aged; Aged, 80 and over; Aspirin - adverse effects; Biological and medical sciences; Cardiovascular Diseases - prevention & control; Cerebrovascular Disorders - prevention & control; Cohort Studies; Female; Fibrinolytic Agents - adverse effects; Humans; Incidence; Male; Medical sciences; Middle Aged; Neurology; Patient Compliance - statistics & numerical data; Primary Health Care - statistics & numerical data; Risk Factors; Stroke - chemically induced; Stroke - epidemiology; United Kingdom - epidemiology; Vascular diseases and vascular malformations of the nervous system; Vascular disease; Stroke; Nervous system diseases; Central nervous system disease; Risk factor; Cardiovascular disease; Acetylsalicylic acid; Cerebrovascular disease; Care; Cerebral disorder
• ISSN: 0028-3878; 1526-632X
• DOI: 10.1212/WNL.0b013e31820d62b5

Discontinuation of low-dose acetylsalicylic acid (ASA) therapy may increase the risk of ischemic events. This study evaluated the risk of ischemic stroke (IS) and TIA after low-dose ASA discontinuation in patients with cardiovascular disease or cerebrovascular disease.
The Health Improvement Network UK primary care database was used to identify a cohort of individuals aged 50-84 years with a first prescription for low-dose ASA (75-300 mg/day) for the secondary prevention of cardiovascular or cerebrovascular events in 2000-2007 (n = 39,512). Individuals were followed up for a mean of 3.4 years to identify cases of IS/TIA. Nested case-control analyses were used to assess risk factors for IS/TIA, including low-dose ASA discontinuation.
The overall incidence of IS/TIA was 5.0 per 1,000 person-years (95% confidence interval [CI] 4.6-5.4). IS/TIA was significantly more common in patients with a previous diagnosis of cerebrovascular disease (relative risk [RR] 2.79; 95% CI 2.05-3.80) or atrial fibrillation (RR 1.71; 95% CI 1.28-2.29) than in those without these conditions. Compared with current users of low-dose ASA, those who discontinued treatment 31-180 days before the index date had a significantly increased overall risk of IS/TIA (RR 1.40; 95% CI 1.03-1.92). The most common reason for discontinuation was patient nonadherence.
In patients prescribed low-dose ASA for the secondary prevention of cardiovascular or cerebrovascular events, discontinuation of low-dose ASA was associated with a 40% increase in the risk of IS/TIA compared with continuation of therapy.
This study provides Class III evidence that discontinuation of low-dose ASA is associated with a 40% increased risk of stroke within 31-180 days of discontinuation.