Recruitment for ASPREE-XT

All ASPREE participants were eligible for enrolment in the ASPREE-XT study. In Australia, ASPREE participants who were attending annual visits during the Bridge period were invited to attend an ASPREE-XT study visit while those who preferred phone contact or were being followed-up via medical records only (MRO) were mailed a study invitation. All groups were mailed an ASPREE-XT participant information and consent form (PICF). Those attending in-person visits were requested to return the paperwork at their next annual visit while those who undertook phone call visits or medical records follow-up were asked to mail the paperwork back using a supplied reply-paid envelope. In the US, ASPREE participants were either mailed out an ASPREE-XT PICF or invited to attend an in-person visit to obtain consent. Regular visit activity resumed in both countries once consent was obtained.

Inclusion and Exclusion Criteria

Inclusion criteria:

• Randomised ASPREE participants in Australia or the US
• Willing and able to provide informed consent, or
• Willing to allow a surrogate representative to provide informed consent
• Willing to accept the study requirements

Exclusion criteria:

• Unable or unwilling to provide informed consent or surrogate representative’s informed consent as appropriate

People who were currently using aspirin for reasons other than secondary prevention entered the trial after agreeing to discontinue aspirin. Chronic use of non-steroidal anti-inflammatory drugs was not an exclusion criterion. During a four week run-in phase participants took placebo for compliance checking. Participants were initially instructed to take their study drug half an hour prior to any morning medication to minimise drug interactions. This instruction was subsequently rescinded.