Results

The baseline characteristics of the ORBITA participants are previously described1. The groups were evenly balanced and prescribing data were available for all 200 randomised participants. Self-reported adherence data and HPLC MS/MS urinalysis data were present for 158 and 195 patients respectively.

Optimisation of medical therapy

At enrolment, prior to optimisation, 82 (78%) and 75 (79%) of patients in the PCI and placebo groups respectively were prescribed aspirin, 71 (68%) and 66 (69%) patients were prescribed a statin and 20 (19%) and 28 (29%) patients were prescribed ≥ 2 anti-anginal agents. By pre-randomization which signifies the end of OMT (Table 2) 102 and (97%) and 92 (97%) patients were prescribed aspirin, 100 (95%) and 91 (96%) were prescribed atorvastatin or other statin and 90 (86%) and 93 (98%) patients were prescribed ≥ 2 anti-anginal agents, in the PCI and placebo groups respectively. Most patients were prescribed two anti-platelet agents, in keeping with guideline-directed clinical practice for elective PCI. The most commonly prescribed, protocol-directed anti-anginal agents were calcium channel blockers - prescribed for 95 (90%) patients that received PCI and 87 (92%) patients that received placebo. Prescription of anti-anginal agents was evenly balanced between the groups, both at pre-randomisation and at follow-up and there was no notable change in prescribing from pre-randomisation to follow-up within groups.

Self-reported medication adherence

Self-reported adherence was >96% for all drugs in both treatment groups at both stages (Table 2).

Urinary HPLC MS/MS

The proportion of expected drug detected was >90% for all first-choice, protocol-directed medicines at both stages. Conversely, percentage adherence below 80% was not demonstrated for any drug at pre-randomisation and was only apparent in patients that were prescribed an alternative statin and who underwent urinary drug detection by HPLC MS/MS at follow-up: 11 of 14 (73%) patients in the PCI group and 2 of 3 (67%) patients in the placebo group.