Kumar 2012.

Methods	RCT, parallel, (fish oil vs nil), 12 months Summary risk of bias: moderate or high
Participants	Patients with persistent atrial fibrillation (AF) on warfarin N: 92 intervention, 90 control (91 and 87 analysed ITT) Level of risk for CVD: high Male %: 82.4 intervention, 72.4 control Mean age in years (SD): 63 (10) intervention, 61(13) control Age range: 18‐85 years (inclusion criteria) Smokers: 22.2% intervention, 11.5% control Hypertension: 45.6% intervention, 58.6% control Medications taken by at least 50% of those in the control group: anti‐arrhythmic drugs, renin‐angiotensin system inhibitors Medications taken by 20%‐49% of those in the control group: statins Medications taken by some, but less than 20% of the control group: not reported Location: Australia Ethnicity: not reported
Interventions	Type: fish oil capsule Comparison: EPA + DHA vs nil Intervention: 6 capsules/day of a fish oil preparation containing a total dose of 1.02 g of EPA and 0.72 g DHA. Participants in the omega‐3 group were asked to continue fish oils till a maximum of 1 year or till return of persistent AF. Dose: 1.7 g/d EPA + DHA Control: no supplements. Patients were advised not to take any fish oil supplements. All patients underwent cardioversion following randomisation. Compliance: was monitored on a weekly basis via telephone and during follow‐up by using a pill count plus serum EPA and DHA levels which were significantly increased Duration of intervention: 1 year (or AF recurrence)
Outcomes	Main study outcome: atrial fibrillation recurrence Dropouts: 4 intervention, 0 control Available outcomes: all‐cause mortality (nil death), AF recurrence, time to AF recurrence, adverse events Response to contact: contact not yet established
Notes	Study funding: the study was funded in part by the National Heart Foundation of Australia and the Pfizer Cardiovascular Lipid Research Grant.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Patients were randomised to a control or an omega‐3 group in a 1:1 fashion (no details of method)
Allocation concealment (selection bias)	Unclear risk	No further details
Blinding of participants and personnel (performance bias) All outcomes	High risk	Open label with no placebo control
Blinding of outcome assessment (detection bias) All outcomes	High risk	Open label
Incomplete outcome data (attrition bias) All outcomes	Low risk	ITT analysis was conducted
Selective reporting (reporting bias)	Unclear risk	Trial registered 2005 but data collection started 2003
Attention	Unclear risk	Intervention group had capsules, while control group did not. Potential for greater contact and checking with intervention group on this basis, although otherwise both groups seem to have had the same care.
Compliance	Low risk	EPA and DHA levels were significantly higher in intervention group
Other bias	Low risk	None noted