Proudman 2015.
| Methods | RCT, parallel, (n3 EPA + DHA high dose vs n3 EPA + DHA low dose), 12 months Summary risk of bias: low |
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| Participants | People with rheumatoid arthritis < 12 months' duration, disease‐modifying anti‐rheumatic drugs (DMARD)‐naive N: 87 intervention, 53 control (analysed, intervention: 75 control: 47) Level of risk for CVD: low Male: 29% intervention, 25% control Mean age (SD): 56.1 (15.9) intervention, 55.5 (14.1) control Age range: unclear Smokers: 65.1% intervention, 54.7% control (includes current & previous smokers) Hypertension: not reported Medications taken by ≥ 50% of those in the control group: triple DMARD therapy (sulfasalazine 0.5 g/d, hydroxychloroquine 200 mg twice/day and methotrexate 10 mg once/week) Medications taken by 20%‐49% of those in the control group: NSAIDS Medications taken by some, but < 20% of the control group: oral or parenteral steroids Location: Australia Ethnicity: not reported |
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| Interventions | Type: supplement (fish oil) Comparison: high EPA + DHA vs low EPA + DHA + MUFA Intervention: 10 mL/d fish oil concentrate (BLT Incromega TG3525) providing 5.5 g/d (3.2 EPA + 2.3 DHA) Control: 10 mL/d Sunola oil:capelin oil (2:1) providing 0·21 g EPA + 0·19 g/d DHA as TG (0.40 g/d EPA + DHA). Sunola oil was stated to be a monounsaturated oil. Dose aim: increase 5.1 g/d EPA + DHA, 2.3% E n‐3, 2.3% E PUFA Baseline PUFA not reported Compliance by biomarkers: unclear, no serum TC reported, plasma phospholipid EPA and DHA reported, but not by intervention group, no other tissue fatty acids reported Compliance by dietary intake: not reported
Compliance by other methods: consumption checked at each visit. 100% compliance would be consumption of 3650 mL oil at 12 months. The fish oil group was less compliant than the control group with median intakes of 2482 mL and 3248 mL, respectively (P = 0.015, Mann‐Whitney U test). This provided an average daily intake of EPA + DHA of 3.7 g and 0.36 g in the fish oil and control groups, respectively. Inclusion basis: compliance data suggested that omega‐3 fats increased by 3.3 g/d EPA + DHA, or 29.7 kcal/d, or 1.5% E. This is > 10% increase of assumed 6% E total PUFA intake at baseline, assuming no or minor PUFA in control (described as MUFA oil). PUFA dose: 1.5% E total PUFA Duration of intervention: 12 months |
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| Outcomes | Main trial outcome: DMARD failure and remission Dropouts: 11 intervention, 6 control Available outcomes: mortality (nil death), adverse events including CVD, Disease Activity Score, diabetes, BMI change Response to contact: yes, trial authors supplied methodology data plus BMI change. |
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| Notes | DAS scores are reported as median and IQR in Proudman 2012 abstract (see Proudman 2015) Trial funding: the trial was supported by ‘the National Health Medical Research Council of Australia and Royal Adelaide Hospital Research Committee. Melrose Health has provided support for ongoing studies.’ The oil used in the trial was made by the Royal Adelaide Hospital Pharmacy |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote: "The randomisation schedule was prepared using an online random number generator and involved randomly permuted blocks of size six." |
| Allocation concealment (selection bias) | Low risk | Quote: "Randomisation was performed by the RAH pharmacy, which also prepared and provided the study oils in 500 mL identical dark brown bottles labelled with consecutive study numbers" |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | Quote: "Both participants and investigators/assessors were blinded to the group allocation. Although the control oil was paler in colour than the fish oil, this was not evident in the brown bottles. The ‘fishy’ odour of each oil was similar." |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | Quote: "Both participants and investigators/assessors were blinded to the group allocation’" Quote: "Investigators and subjects remained blinded for all withdrawals." |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | The flow of all trial participants shown in FIGURE 2 |
| Selective reporting (reporting bias) | Unclear risk | Outcomes reported in trial register matched with the outcomes reported in publications. However, the trial was retrospectively registered ‐ registered in 2013, recruitment began in 2001. |
| Attention bias | Low risk | No difference between groups |
| Compliance | Unclear risk | No TC reported, plasma phospholipid EPA and DHA reported, but not by intervention group, no other tissue fatty acids reported |
| Other bias | Low risk | None noted |