Summary
It was the aim of this study to investigate whether low-dose acetylsalicylic acid
(ASA) therapy for secondary cardiovascular prevention should continue, despite the
risk of gastrointestinal bleeding. We aimed to make a clinically meaningful benefit–risk
assessment regarding the cardiovascular and gastrointestinal consequences of ASA discontinuation.
This case–control study used The Health Improvement Network UK primary care database
to identify patients aged 50–84 years during 2000–2007 with a first ASA prescription
for secondary cardiovascular prevention (N = 39,513). New cases of non-fatal myocardial
infarction (MI)/coronary death (n = 1,222), ischaemic stroke (IS)/transient ischaemic
attack (TIA) (n = 673) and upper gastrointestinal bleeding (UGIB) (n = 169) were identified
after a mean follow-up of 3.2, 3.4 and 4.0 years, respectively. ASA discontinuers
before the index date were identified. Attributable risks associated with ASA discontinuation
were calculated and National Institute for Health and Clinical Excellence annual economic
data were used to estimate healthcare costs. The cumulative incidences of non-fatal
MI/coronary death, IS/TIA and UGIB among ASA discontinuers within the first year of
follow-up were 17, 11 and 1.6 per 1,000 persons, respectively. This corresponds to
eight extra cardiovascular events, and a reduction of 0.4 UGIB events per year compared
with current ASA users. Extrapolating to the UK population aged over 50 years, avoiding
discontinuation of ASA could prevent 12,786 coronary and 7,672 cerebrovascular events/year,
at the expense of 1023 extra UGIB events, saving approximately £100 million/year.
In conclusion, preventing patients with cardiovascular disease from discontinuing
ASA could result in substantial clinical and economic gains.
Keywords
Aspirin - medication adherence - Primary Health Care - cardiovascular - gastrointestinal
haemorrhage
