U-TXM study.
APPENDIX
Urine samples were collected at trial entry (off aspirin), after an 8-week run-in period of aspirin 100 mg daily for all participants and 3–6 months after random allocation to aspirin 100 mg, aspirin 300 mg or matched placebo daily.End of run-in, and post-randomisation, urine samples were only included in this analysis if the participant had remained on allocated treatment. Adherence was assessed by participant self-reporting and review of used blister packs/completion of diary cards at the end of the run-in period. Based on these assessments participants were included if they had taken 6–7 tablets per week and had not discontinued treatment prior to the urine sample being obtained.Urine samples were sent by post from trial centres to one of two trial biobanks in the UK within 24 h of collection. Aliquoted into 2-ml cryo-vials, frozen at −20 °C or below and transferred on dry ice to the Institute of Pharmacology at the Catholic University School of Medicine (Rome, Italy). The extraction procedure was performed on 1 ml urine samples as described in detail in Supplementary Appendix S