OASIS 5.

Methods	Randomised, multicentre, prospectively designed substudy of the OASIS 5 trial (a double‐blinded trial in which fondaparinux was compared with enoxaparin in participants with UA/NSTEMI).
Participants	184 female participants were recruited when the OASIS 5 main trial was stopped. These participants presented to hospital with symptoms of UA or MI without persistent ST elevation and at least 2 of: age ≥ 60 years, troponin T or I or CK‐MB above the upper limit of normal or ECG changes compatible with ischaemia (ST depression ≥ 1 mm in 2 contiguous leads or T wave inversion > 3 mm or any dynamic ST shift or transient ST elevation). Overall impression of level of risk in participants: intermediate risk.
Interventions	Conservative/selective invasive arm: with coronary angiography only if symptoms or signs of severe ischaemia. Invasive arm: routine coronary angiography within 4 days of admission and, if appropriate, revascularisation within 7 days of admission.
Outcomes	Primary endpoint was the composite of death, MI or stroke at 2 years. Secondary outcomes included the following. Death, MI, and stroke evaluated separately. Composites of death, MI and death, MI, stroke or refractory ischaemia.
Notes	Recruitment ceased early and sample sizes curtailed.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer generated permuted block randomisation, stratified according to study centre using predetermined site specific randomisation ratios of 1:1, 1:2 or 2:1 for early intervention:delayed intervention in block sizes of 2 and 4. There were no significant differences in baseline characteristics of groups.
Allocation concealment (selection bias)	Low risk	Allocations were concealed at the Canadian Cardiovascular Collaboration Project Office, Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, Canada and accessed via 24‐hour computerized telephone service.
Blinding (performance bias and detection bias) All outcomes	High risk	Open.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	A central committee of clinicians blinded to the allocated management strategy adjudicated death classified by cause, MI, refractory ischaemia, stroke and major bleeding.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Nine participants were lost to long‐term follow‐up, equally distributed between routine invasive (5) and selective invasive (4) strategies. The trial used ITT analysis.
Other bias	Unclear risk	Curtailment in sample size as well as follow‐up time. Sponsored by Sanofi‐Aventis, Organon and GlaxoSmithKline. The sponsor reportedly did not have a role in the study design; the collection, analysis, or interpretation of the data; the preparation, review or approval of the manuscript.