THIS DIET 2008

Methods	The Heart Institute of Spokane Diet Study (THIS‐DIET) RCT‐ parallel, 24 months Summary risk of bias: moderate or high
Participants	Recent survivors of first myocardial infarction (within < 6 weeks) N: 51 intervention, 50 control Level of CVD risk: high Men: 80% intervention, 68% control Mean age in years (SD): 58 (10) intervention, 58 (9) control Age range: unclear Smokers: 25% intervention, 30% control Hypertension: 43% intervention, 50% control (uncontrolled or secondary hypertension excluded) Medications taken by at least 50% of those in the control group: aspirin, statins, beta‐blockers, and ACE inhibitors or angiotensin receptor blockers. Medications taken by 20%‐49%: not reported Medications taken by some, but < 20%: not reported Location: USA Ethnicity: intervention 98% white; control 94% white
Interventions	Type: dietary advice (to follow a Mediterranean style diet high in n‐3) Comparison: EPA + DHA vs MUFA (biggest dietary change) Intervention: Mediterranean style diet high in n‐3. Dietary counselling group sessions; two in first month then at months 3, 6, 12 and 24. Sessions focused on behaviour modification and practical aspects of assigned diet including recipes, shopping and dining out. Aim to increase omega 3 fat intake to > 0.75% kcal. Dose: ˜1.5 g/d omega 3 fat, or 0.31% E by intake assessment. Control: dietary advice (to follow the American Heart Association Step II diet). Same number of group sessions as intervention. The 2 diets were low in saturated fat (< 7% kcal) and cholesterol (< 200 mg/day); the Mediterranean‐style diet was distinguished by greater omega‐3 fat intake (> 0.75% kcal). Compliance: participants were required to attend six sessions and only invited but not required to attend extra sessions. 3‐day food diaries were reviewed with dietitians. Compliance results not stated. Dietary achievements: Total fat intake, % E (at 24 months): control 29.7 (SD 9.3), intervention 29.1 (SD 8.6) Saturated fat intake, % E (at 24 months): control 8.0 (SD 2.9), intervention 7.9 (SD 3.2) PUFA intake, % E (at 24 months): control 5.7 (SD 3.1), intervention 5.7 (SD 2.4) PUFA n‐3 intake, % E: control 0.46 (SD 0.38), intervention 0.67 (SD 0.35) g/week PUFA n‐6 intake: not reported MUFA intake, % E (at 24 months): control 10.3 (SD 5.1), intervention 9.7 (SD 3.6) CHO intake, % E (at 24 months): control 54 (SD 11), intervention 54 (SD 10) Protein intake, % E (at 24 months): control 17 (SD 2), intervention 18 (SD 3) Trans fat intake: not reported Length of intervention: 24 months
Outcomes	Main study outcome: a composite of endpoints including all‐cause and cardiac death, MI, hospital admissions for heart failure, unstable angina, or stroke Dropouts: none for primary outcomes Available outcomes: total and CVD deaths (nil deaths), CV events, stroke, MI, diagnosis of diabetes mellitus, BMI and weight (different at baseline hence not used), waist circum, lipids, blood pressure, albuminuria, CRP, creatinine and dietary intake (authors supplied further data on newly diagnosed DM, glucose and insulin data, cancers, depression, atrial fibrillation) Response to contact: yes further data supplied as above
Notes	The study compared the 2 intervention groups to a non‐randomised usual care control group (not reported here) Study funding: no funding details is provided but some reported conflict of interests for an author.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Sealed envelopes concealing the allocation sequence were prepared by a research coordinator. Assignment was stratified by diabetes mellitus status using 10‐envelope blocks. Envelopes were selected in the prepared order from a locked drawer by a study dietitian to assign interventions
Allocation concealment (selection bias)	Unclear risk	As above but opacity of envelopes is not stated.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Neither the intervention team nor participants could be blinded to dietary assignment.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The PI was blinded for the purpose of adjudicating clinical end points and adverse events by the removal of identifiers from records used for review.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Primary outcomes data provided for all randomised
Selective reporting (reporting bias)	High risk	NCT00269425. Trial was registered in 2005, data collection started in October 2000, January 2008 (final data collection date for primary outcome measure), publication 2008. A number of the outcomes from the registration were not reported e.g. cardiovascular revascularisation, peripheral revascularisation or amputation, doubling of serum creatinine, dialysis, or kidney transplant, new hypertension. Also numerous secondary measures were reported that were not in the original registration.
Attention	Low risk	Both arms had the same contact and attention
Compliance	Unclear risk	No details
Other bias	Low risk	None noted