AlphaOmega ‐ ALA 2010.
Methods | RCT, (n‐3 ALA vs MUFA), 40 months Summary risk of bias: low |
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Participants | 60‐80 year‐olds with previous MI N: 1197 ALA intervention, 1236 control (1212 ALA + EPA/DHA intervention group) Level of risk for CVD: high Men: 77.9% intervention, 78.7% control Mean age in years (SD): 69.0 (5.6) intervention, 68.9 (5.6) control Age range: 60‐80 years Smokers: 17.4% intervention, 18% control Hypertension: unclear Medications taken by at least 50% of those in the control group: lipid lowering medication, antihypertensives, antithrombotics 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: antiarrythmic drugs, antidiabetic drugs Location: the Netherlands Ethnicty: not reported |
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Interventions | Type: supplementary margarine Comparsion: ALA vs MUFA Intervention 20 g of enriched margarine per day incorporating: 2 g ALA. 8 × 250 g margarine tubs delivered every 12 weeks. Dose: average achieved +1.9 g/d ALA Control: 20 g of margarine per day. No additional n‐3 PUFAs. Identical margarine (oleic acid) placebo. Compliance: unused margarine tubs were returned‐ daily intakes of margarine and n‐3 fatty acids were calculated on the basis of the amount unused. Adherence was measured by levels of fatty acids in plasma cholesteryl esters, margarine and questionnaires. 90.5% of patients adhered to the protocol and consumed 20.6 (SD 2.8) g of margarine/d. Length of intervention: 40 months |
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Outcomes | Main study outcome: cardiovascular disease events Dropouts: 91 died, 98 discontinued intervention, 93 died, 93 discontinued control Available outcomes: deaths, MI, cardiovascular events, ventricular arrhythmia, Incident cardiovascular disease Response to contact: yes (data provided) |
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Notes | The study has 3 intervention arms (ALA margarine, EPA/DHA margarine, mixture of the two interventions). This table represents the ALA only intervention. Outcome data is used for the ALA group where reported separately or for the combined (ALA arm, ALA + EPA/DHA arm) Study funding: Netherlands Heart Foundation, National Institutes of Health and Unilever R&D (latter provided unrestricted grant for distribution of trial margarines) |
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Risk of bias | ||
Bias | Authors' judgement | Support for judgement |
Random sequence generation (selection bias) | Low risk | On the computer by a random number generator before the start of the trial |
Allocation concealment (selection bias) | Low risk | Author confirmed allocation was concealed from clinicians/ researchers |
Blinding of participants and personnel (performance bias) All outcomes | Low risk | The 4 types of margarine were "similar in taste, texture and colour". A trained test panel did not perceive a fishy taste or odour. Randomisation tables were stored safely under supervision. |
Blinding of outcome assessment (detection bias) All outcomes | Low risk | Randomisation tables were stored safely under supervision. There was an independent statistician for data analysis. Quote: "Events were coded by three members of the end‐point adjudication committee who were unaware of the identity of the patient, the identity of the treating physician and the patients assigned study group". |
Incomplete outcome data (attrition bias) All outcomes | Low risk | All patients were followed up for events computerised linkage with municipal registries. 2531 patients were only followed up for baseline anthropometric and medical measurements. |
Selective reporting (reporting bias) | High risk | Sudden cardiac death endpoint omitted. Registered in August 2005, recruitment was from 2002 to 2006. Outcomes papers published in 2010 |
Attention | Low risk | All participants appear to have had similar frequency and quantity of attention and follow‐up |
Compliance | Low risk | Unused margarine tubs were returned; daily intakes of margarine and n‐3 fatty acids were calculated on the basis of the amount unused. Adherence was measured by levels of fatty acids in plasma cholesteryl esters, margarine and questionnaires. 90.5% of patients adhered to the protocol and consumed 20.6 (SD 2.8) g of margarine/d |
Other bias | Low risk | None noted |