Gastrointestinal Safety of Aspirin for a High-Dose, Multiple-Day Treatment Regimen: A Meta-Analysis of Three Randomized Controlled Trials

BACKGROUND AND AIM: Aspirin is a commonly used over-the-counter (OTC) agent for the symptomatic treatment of acute pain, fever, or the common cold, but data regarding safety in this context are limited. In order to characterize the safety of aspirin beyond single-dose or long-term use data, we conducted a meta-analysis of multiple-dose, multiple-day studies of OTC aspirin at a label-approved dosage. METHODS: We conducted a meta-analysis of individual patient data from three Bayer-sponsored studies. The meta-analysis was performed in 2015; the individual studies were conducted between 2008 and 2012 and were of a randomized, parallel-group, placebo-controlled design. Patients received a minimum dosage of aspirin of 2000 mg/day over at least 3 days. The endpoints were patient-reported adverse events (AEs) with an emphasis on the system organ class gastrointestinal system. Event incidences were estimated and an analysis of the odds ratios (ORs) and risk differences (RDs) of aspirin versus placebo were performed. RESULTS: Of the 819 patients included, 433 were treated with aspirin and 386 were treated with placebo. The majority of patients (85.7 %) received a median dose of aspirin of 3000 mg/day for 3 days. The incidence of the overall AEs was low and rates were comparable between the aspirin (10.9 %) and placebo (12.4 %) groups [OR: 0.86 (95 % confidence interval [CI] 0.56, 1.34); RD: −1.49 (95 % CI −6.01, 3.03)]. Gastrointestinal AEs were more common in subjects treated with aspirin (7.4 %) than with placebo (5.4 %), and although this difference did not reach statistical significance, a trend towards increased risk was observed with aspirin use [OR: 1.41 (95 % CI 0.78, 2.54); RD: 2.00 (95 % CI −1.35, 5.35)]. Nausea, upper abdominal pain, dyspepsia, and diarrhea were the most frequently reported gastrointestinal AEs. There were no reports of serious gastrointestinal complications such as bleeding, perforation, or ulceration. CONCLUSIONS: The multiple-dose regimen of aspirin used for several days according to the OTC label is well-tolerated by otherwise healthy non-elderly subjects for short-term and symptomatic treatment of pain, fever, and the common cold. There were no reports of serious gastrointestinal complications in either of the groups.