Dalakas 2001.

Methods	Randomised, double‐blind, placebo‐controlled study
Participants	37 randomised participants (gender unspecified) Treated group mean age: 68.21 (no SD or range) years Placebo group mean age: 68.35 (no SD or range) years. Duration of symptoms not given. Inclusion criteria: diagnostic criteria for sporadic IBM; active disease characterised by progressive muscle weakness that impaired ability to perform independently various activities of daily living such as walking without falls, dressing, buttoning, or climbing up stairs; ambulatory independently or with assistance Exclusion criteria: wheelchair‐bound patients; coronary artery disease; immunoglobulin A deficiency; kidney dysfunction; any systemic illness.
Interventions	IVIg and prednisone versus placebo and prednisone for 3 months
Outcomes	Primary outcome measure(s) Change in MMT sum scores MMT was completed for 13 muscle groups and muscle group actions bilaterally (although 12 specified): deltoid; biceps brachii; triceps brachii; brachioradialis; wrist extensors; wrist flexors; iliopsoas; gluteus maximus; quadriceps femoris; hamstrings; foot extension or flexion. Muscle strength was graded on a modified (0 to 10) MRC scale (Brooke 1983). Change in QMT sum scores QMT was examined for the following muscle group actions: shoulder abduction; forearm flexion and extension; hip flexion; leg extension and flexion; foot extension. Secondary outcome measure(s) Change in participants’ assessment of their response to therapy, categorised as "felt better and performed more", "felt weaker", or "no change" Histological features were also assessed in repeated biopsies.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	The investigators describe a random component in the sequence generation process: "The patients were assigned to receive IVIg or placebo by a block‐randomization procedure".
Allocation concealment (selection bias)	Low risk	Central allocation: "Randomization was performed at the pharmacy".
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Insufficient information to permit judgement: "The principal investigator, the physicians, nurses, physical therapists, and statisticians were unaware of which type of the IV infusion was administered" and based on participants' own assessment "no apparent signs to unblind any of the patients were observed." However, only the assessor of QMT and not MMT is confirmed to have remained blinded, suggesting that blinding of key personnel could have been broken.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information to permit judgement: as above, only the assessor of QMT is confirmed to have "remained blinded".
Incomplete outcome data (attrition bias) All outcomes	Low risk	Number of participants randomised and reasons for missing data stated; 1 dropout (died from myocardial infarction on placebo infusion) not analysed. No statistical analysis for the incidence of adverse events was completed.
Selective reporting (reporting bias)	Low risk	The study protocol is not available, but outcomes prespecified in the methods are all reported in the results.
Other bias	Unclear risk	Insufficient information to permit judgement, but potential carry‐over effect of previous treatment(s): "Several patients had been treated previously with high‐dose prednisone or therapeutic doses of another immunosuppressant (methotrexate, azathioprine), but they had not been taking any such medicine up to 3 months before enrollment".