Couture 1998

Methods	* Design: RCT * Randomization process: nr * Blinding: double * Concealment of allocation: nr * Setting: 1 research clinic * Country: Canada * Follow‐up: 6 weeks
Participants	* Individuals with HeFH (N = 63) * Diagnosis: unclear, LDL‐C > 95th percentile on diet * Inclusion: age < 18 years; HeFH; LDL‐C > 95th percentile on diet; * Exclusion: DM; anorexia; kidney, liver or thyroid disorder; delayed puberty * Base population: all potential participants screened * Age 8 ‐ 17 years * Male 59% * Race: nr * Height (mean) 153 cm * weight (mean) 46 kg * BMI (mean) nr * LDL‐C (mean) 5.8 mmol/L
Interventions	* Treatment: simvastatin 20 mg daily (n = 47) * Control: placebo (n = 16) * Run‐in: placebo 4 weeks * Diet: AHA phase I, dietary counselling throughout the trial
Outcomes	LDL‐C: enzymatic method, calculated Friedewald's formula TC: enzymatic method HDL‐C: heparin‐manganese chloride method TG: enzymatic method
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as randomized, process not reported.
Allocation concealment (selection bias)	Unclear risk	nr
Blinding (performance bias and detection bias) All outcomes	Low risk	Double blind
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Compliance: nr Dropout: nr Losses to follow‐up: 0% Missing from analysis: 0%
Selective reporting (reporting bias)	Unclear risk	No indication to suspect selective reporting.