Erdogan 2007

Methods	RCT, parallel (n‐3 EPA + DHA vs unclear), 12 months Summary risk of bias: moderate to high
Participants	People with successful external cardioversion N: unclear intervention, unclear control (54 analysed intervention, 54 control) Level of risk for CVD: high Men: 70% intervention, 74% control Mean age in years (SD): 65.0 (mean for whole group, SD not reported) Age range: not reported Smokers: not reported Hypertension: not reported 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: Germany Ethnicity: not reported
Interventions	Type: supplement (probably, not described) Comparison: high EPA + DHA vs unclear placebo Intervention: described only as "PUFA" but included in systematic review (Mariani 2013) by Erdogan et al on effects of n‐3 PUFA. Dose: unclear Control: described only as "placebo" Compliance: not reported Length of intervention: 12 months
Outcomes	Main study outcome: atrial fibrillation relapse Dropouts: not reported Available outcomes: recurrent AF (reported in Mariani 2013), mortality (none) Response to contact: no reply to date
Notes	Funding source: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "randomly assigned"
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Described as triple blind, but no further details provided (only an abstract with some details in a related trial publication and some in a systematic review by the same author)
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not described, but analysis appears to have been carried out blind to intervention/control status
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Number randomised not described
Selective reporting (reporting bias)	Unclear risk	Unclear, no trial registry entry or protocol found
Attention	Unclear risk	Not described
Compliance	Unclear risk	Not described
Other bias	Low risk	None noted