EVAR1.
| Methods |
Study design: Multicentre RCT Method of randomisation: Permuted block randomisation Exclusions post randomisation: 37 participants excluded. 31 died before surgery (EVAR = 12; OSR = 19); 5 refused surgery (all OSR), 2 postponed surgery (EVAR = 1; OSR = 1) Losses to follow up: 17 (EVAR = 9; OSR = 8) Intention‐to‐treat analysis: Yes |
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| Participants |
Country: UK Setting: Hospital (37 centres) Recruitment: 1 September 1999 to 31 August 2004 Number: 1252 (EVAR = 626; OSR = 626) Age: Mean (SD) = 74.1 (6.1) years Sex: Male:female = 10:1 Inclusion criteria: Aged ≥ 60 years with AAA ≥ 5.5 cm in any plane, assessed by CT Exclusion criteria: Participants unsuitable for EVAR or unfit for operation |
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| Interventions |
Treatment: EVAR Control: OSR |
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| Outcomes |
Primary: All‐cause mortality Secondary: Aneurysm‐related mortality; incidence of postoperative complications; secondary interventions; HRQoL and hospital costs and durability |
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| Notes | Results from this trial were published at different stages of recruitment and follow up. Data for outcomes were taken from the most relevant publication and this is reflected in the total number of participants for some outcomes | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "Randomisation is performed for each trial using a 50:50 ratio randomly permuted block sizes constructed by the STATA package. Randomisation is stratified by centre and is performed centrally by the trial manager only when all necessary baseline data had been received at the trial co‐ordinating centre" |
| Allocation concealment (selection bias) | Low risk | Allocation was done only after all baseline data were recorded |
| Blinding of participants and personnel (performance bias) All outcomes | Unclear risk | Blinding of participants and operating surgeons not feasible in such a study |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | No clear data available |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Analysis was intention‐to‐treat basis; all participants accounted for |
| Selective reporting (reporting bias) | Low risk | Reported on all predefined outcomes |
| Other bias | Low risk | None identified |