Puri 2005

Methods	RCT, parallel (ethyl‐EPA vs paraffin), 2 arm, 12 months Summary risk of bias: low
Participants	People with Huntington's Disease N: 67 intervention, 68 control (analysed, intervention: 39 control: 44) Level of risk for CVD: low Men: 57% intervention, 44% control Mean age in years (SD): 50 (9.3) intervention, 49 (9.0) control 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: antidepressants Medications taken by some, but < 20%: neuroleptics Location: UK, USA, Canada, Australia Ethnicity: intervention: 94% white, 4% black, 1% Asian; control: 97%, 3%, 0%, respectively
Interventions	Type: supplement (ethyl‐EPA) Comparison: EPA vs paraffin (non‐fat) Intervention: 2 × 2 × 500 mg capsules/d, total dose of 2 g/day ethyl‐EPA (code name LAX‐101, purity 95%). Dose: 1.9 g/d EPA Control: 2 × 2 × 500 mg capsules/d liquid paraffin Compliance: 38 were excluded for protocol violations, 4 intervention and 16 control were non‐compliant with capsules Duration of intervention: 12 months
Outcomes	Main study outcome: functional status in Huntington's Disease Dropouts: 7 intervention, 7 control Available outcomes: measures of functional capacity, CV events, cancers (nil deaths) Response to contact: yes (no additional data provided)
Notes	Study funding: Amarin Neuroscience Ltd. (formerly known as Laxdale Ltd.), provided organisation, funding and salaries
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "After screening and acceptance... patients were assigned to treatment by receiving a numbered pack supplied by a clinical trials packaging organization ... independent of all other aspects of the trial. Randomization was stratified in a block size of four, with the appropriate number of blocks allocated to each center. PCI Clinical Services held the randomization code until the database had been closed and all patients had been assigned"
Allocation concealment (selection bias)	Low risk	As above
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "[p]lacebo and ethyl‐EPA capsules were of identical appearance" (though taste and smell not reported).
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Randomisation described as "double‐blind", "neither the patients nor the participating medical staff had access to this code during the course of the study"
Incomplete outcome data (attrition bias) All outcomes	High risk	Clearly reported and complete, however > 20% attrition
Selective reporting (reporting bias)	Unclear risk	No protocol or trials registry entry identified
Attention	Low risk	Unlikely
Compliance	Unclear risk	38 were excluded for protocol violations, 4 intervention and 16 control were non‐compliant with capsules
Other bias	Low risk	None noted