| Methods | RCT, parallel, (fish oil or olive oil), 24 months Summary risk of bias: moderate or high |
|
| Participants | People with implantable cardioverter defibrillators and recent sustained ventricular tachycardia or ventricular fibrillation (VT/VF) N: 100 intervention, 100 control Level of risk for CVD: high Men: 86% intervention, 86% control Mean age in years (SD): 63 (13) intervention, 62 (13) control Age range: not reported but 18‐75 inclusion criteria Smokers: not reported Hypertension: 46% intervention, 55% control Medications taken by at least 50% of those in the control group: diuretic, beta blockers, ACE inhibitors Medications taken by 20%‐49% of those in the control group: digoxin, statins Medications taken by some, but less than 20% of the control group: calcium channel blocker Location: USA Ethnicity: 94% white in intervention group, 97% in control group |
|
| Interventions | Type: supplement (fish oil capsules vs olive oil capsules) Comparison: EPA + DHA vs MUFA Intervention: 1.8 g/d fish oil capsules (Hoffman LaRoche, including ethyl esters of EPA and DHA, 0.76 g/d EPA, 0.54 g/d DHA). Dose: 1.3 g/d EPA + DHA Control: 1.8 g/d olive oil capsules (Hoffman LaRoche, 73% oleic acid) Compliance: while control group plasma and platelet DHA and EPA did not change, there were increases of 2%‐8.3% in the intervention group Duration of intervention: 24 months (median 718 days) |
|
| Outcomes | Main study outcome: time to first episode of VT/VF Dropouts: 17 intervention, 26 control Available outcomes: deaths, CV death, MI, angina, revascularisation, arrhythmias, sudden cardiac death, cancer Response to contact: yes but no data provided |
|
| Notes | Study funding: NIH and Hoffman LaRoche | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote: "computer generated block randomisation scheme" |
| Allocation concealment (selection bias) | Unclear risk | Not described |
| Blinding of participants and personnel (performance bias) All outcomes | Unclear risk | Participant blinding unclear |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | ICD traces were viewed by researchers blinded to allocation, "double blind placebo‐controlled" |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Almost all participants were included in outcome assessment, well described |
| Selective reporting (reporting bias) | High risk | NCT registered in February 2000, study carried out from February 1999 to January 2004. Most outcomes stated in registry entry reported, but quality of life missing |
| Attention | Low risk | Capsules were the only different interventions between arms, little opportunity for attention bias |
| Compliance | Low risk | While control group plasma and platelet DHA and EPA did not change, there were increases of 2%‐8.3% in the intervention group |
| Other bias | Low risk | None noted |
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