Lok 2012.

Methods	Study design: multicenter, randomised, placebo‐controlled clinical trial
Participants	Country: 12 Canadian and 3 United States sites No. of participants randomised: 201 No. of participants who started the study intervention: 196 No. of participants who completed the trial: 164 (5 excluded prior to receiving treatment, 32 did not complete 12 months follow‐up) Age: 27 to 88 years Gender: M = 98, F = 98 Inclusion criteria: adults (≥ 18 years) who required a synthetic arteriovenous graft for chronic haemodialysis. The graft could be either a ‘first access’ or a ‘subsequent access’ after a previously failed access Exclusion criteria: reversible renal failure; active malignancy; pregnancy; malignant hypertension; active major bleed in the prior month; receiving more than 2 antiplatelet agents or anticoagulants; life expectancy less than 6 months; surgical revision of a previous access; arteriovenous graft that failed prior to and including postoperative day 7; ingestion of any form of fish oil at time of randomisation; allergy to fish or fish products; enrolment in another interventional study of arteriovenous grafts
Interventions	Treatment: four 1 gram fish oil capsules per day. Each capsule was MEG‐3 (Ocean Nutrition Canada Ltd), which contained 48% (400 mg/capsule) eicosapentaenoic acid (EPA) and 25% (200 mg/capsule) docosahexaenoic acid (DHA) Control: 4 placebo capsules per day containing 1% peppermint‐flavoured corn oil Duration: 12 months
Outcomes	Primary: proportion with loss of native patency within 12 months Secondary: rate and proportion of graft thrombosis, proportion with radiological or surgical intervention, cumulative graft patency, cardiovascular outcomes
Notes	Synthetic arteriovenous grafts Premature termination due to slow recruitment and lack of additional funds decreased study power from 80% to 74%
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Concealed allocation by central independent randomisation facility with stratification by site and first access or subsequent access
Allocation concealment (selection bias)	Low risk	No pre‐allocation bias
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Stated that participants, study coordinators, care‐givers and site pharmacists were blinded to treatment allocation
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Assessment undertaken by an independent assessor who was blinded to treatment allocation
Incomplete outcome data (attrition bias) All outcomes	Low risk	Five participants excluded after randomisation, but before treatment initiated. All participants were included in the primary analysis, even if they didn't complete follow‐up
Selective reporting (reporting bias)	Low risk	Pre‐study protocol available
Other bias	Low risk	Nil obvious