Birnbaum 2008.

Methods	RCT with parallel design, The method of randomisation and allocation concealment was not mentioned in the original article in detail. After correspondence with the author, Dr. Birnbaum quickly responded to our requests, he said patients were randomly allocated using a computer random number generator and the allocation sequence was using sequentially numbered, opaque, sealed envelopes to make sure the participants and investigators unpredict the assignment. Double blinded: all study personnel, participants and outcome assessors were blinded. Drop‐outs: Intervention group: 3 (1 due to muscle aching and weakness, 1 elevation in AST and ALT, 1 for unknown reasons); Control group: 1 elevated CK levels. Losses to follow‐up: 1 in statins group for unknown reasons. Treatment duration: 6 months. Follow‐up period: 9 months. Intention‐to‐treat analysis: yes.
Participants	26 patients with clinically definite relapsing‐remitting MS according to Poser or McDonald criteria Participants were enrolled to the study only if clinically stable for at least 6 months Characteristics of patients at baseline: similar Sex: G1 F/M: 6/3, G2 F/M: 6/1, G3 F/M: 8/2 Mean age: G1 40.1 ± 9.2 years, G2 38.4 ± 7.5 years, G3 45.1 ± 6.3 years Disease duration: G1 7.7 ± 7 years, G2 6.4 ± 6.7 years, G3 7.2 ± 5.9 years Baseline mean EDSS: G1 2.3 ± 1.4, G2 2.1 ± 0.6, G3 2.0 ± 0.7
Interventions	Group 1: IFN + 40 mg/d placebo + 40 mg/d placebo Group 2: IFN + 40 mg/d atorvastatin + 40 mg/d placebo Group 3: IFN + 40 mg/d atorvastatin + 40 mg/d atorvastatin atorvastatin and placebo were provided by the manufacturer, Pfizer, with the same shape and size.
Outcomes	(1) Clinical relapses (2) New or enhancing T2 lesions (3) Laboratory blood testing (4) Safety and tolerability
Notes	The study was funded by the manufacturer, Pfizer, moreover, Dr. Birnbaum, Dr. Altafullah and Dr. Reder have received honoraria and research support from Pfizer. Relapses were defined as new neurologic symptoms accompanied by corresponding neurologic deficits that persisted for greater than 24 hours in the absence of fever or other bodily stressors.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer random number generator
Allocation concealment (selection bias)	Low risk	Adequate
Blinding (performance bias and detection bias) All outcomes	Low risk	Double blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	Missing data and reasons were carefully recorded, and balanced between groups.
Selective reporting (reporting bias)	Low risk
Other bias	Unclear risk	Conflict of interests may exist