Adult Japanese MEGA Study.

Study characteristics
Methods	Randomised trial.
Participants	7832 participants with hypercholesterolaemia based in Japan aged 40‐70 (mean age 59); 32% men. None with any clinical evidence of CVD.
Interventions	10‐20 mg pravastatin versus placebo; all participants got advice on diet; follow‐up 5 years.
Outcomes	Primary: composite of major CVD events, sudden cardiac death, angina and revascularisation. Single outcomes included: all‐cause mortality, total CVD events, fatal and non‐fatal MI, stroke and TIA events, sudden cardiac death, angina and revascularisation, cholesterol, adverse events.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computerised randomisation by permuted block method.
Allocation concealment (selection bias)	Low risk	Central laboratory.
Blinding (performance bias and detection bias) All outcomes	High risk	Single blinded, endpoint committee was blinded only because investigators stated that placebo‐controlled trials are regarded with suspicion by Japanese participants
Incomplete outcome data (attrition bias) All outcomes	Low risk	ITT used 2% dropped out.
Selective reporting (reporting bias)	High risk	Not all adverse events reported. We wrote to the authors asking for clarity regarding data on serious events. The authors responded saying they were unable to send the data.
Other bias	Low risk	Groups were comparable at baseline and includes all the major prognostic factors. Funded by pharmaceutical industry.