Risk of gastrointestinal haemorrhage with long term use of aspirin: meta-analysis

Abstract

Objectives: To assess the incidence of gastrointestinal haemorrhage associated with long term aspirin therapy and to determine the effect of dose reduction and formulation on the incidence of such haemorrhage.

Design: Meta-analysis of 24 randomised controlled trials (almost 66 000 participants).

Intervention: Aspirin compared with placebo or no treatment, for a minimum of one year.

Main outcome measures: Incidence of gastrointestinal haemorrhage.

Results: Gastrointestinal haemorrhage occurred in 2.47% of patients taking aspirin compared with 1.42% taking placebo (odds ratio 1.68; 95% confidence interval 1.51 to 1.88); the number needed to harm was 106 (82 to 140) based on an average of 28 months' therapy. At doses below 163 mg/day, gastrointestinal haemorrhage occurred in 2.30% of patients taking aspirin compared with 1.45% taking placebo (1.59; 1.40 to 1.81). Meta-regression showed no relation between gastrointestinal haemorrhage and dose. For modified release formulations of aspirin the odds ratio was 1.93 (1.15 to 3.23).

Conclusions: Long term therapy with aspirin is associated with a significant increase in the incidence of gastrointestinal haemorrhage. No evidence exists that reducing the dose or using modified release formulations would reduce the incidence of gastrointestinal haemorrhage.

Figures

Figure 1

Peto odds ratio for gastrointestinal haemorrhage with aspirin. SALT=Swedish aspirin low dose trial; TPT=thrombosis prevention trial; USPHS=US physicians health study; EAFT=European atrial fibrillation trial; UK-TIA=UK transient ischaemic attack aspirin trial; CDPA=coronary drug project aspirin study; PARIS=persantine-aspirin reinfarction study; AMIS=aspirin myocardial infarction study; CCSG=Canadian Cooperative Study Group

Figure 2

Meta-regression of Peto odds ratio for gastrointestinal haemorrhage against dose of aspirin (size of circle is proportional to size of trial)