Sianni 2013.

Methods	RCT, parallel, (fish oil vs placebo), 12 months Summary risk of bias: moderate or high
Participants	Patients with hypertension and paroxysmal or persistent atrial fibrillation (AF) N: 268 intervention, 60 control Level of risk for CVD: moderate Men: not reported Mean age (SD) years: 62 (6), not reported by arm Age range: not reported Smokers: not reported Hypertension: 100% Medications taken by at least 50% of those in the control group: not reported Medications taken by 20%‐49% of those in the control group: not reported Medications taken by some, but less than 20% of the control group: not reported Location: Greece Ethnicity: not reported
Interventions	Type: supplement Comparison: fish oil vs unclear placebo Intervention: omega‐3 fatty acids with no further details. Dose: 4 g/d omega Control: placebo, no further details Compliance: no details Duration of intervention: 12 months
Outcomes	Main study outcome: AF recurrence and BP Dropouts: no details Available outcomes: new AF episodes, BP (not in a usable format) Response to contact: no
Notes	Study funding: unclear The study's only publication was a conference abstract.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details, probably randomised but unclear
Allocation concealment (selection bias)	Unclear risk	No details
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	No details
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No details
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No details
Selective reporting (reporting bias)	Unclear risk	No protocol or trial register record found
Attention	Unclear risk	No details
Compliance	Unclear risk	No details
Other bias	Unclear risk	No details