Guillaume 1993.

Study characteristics
Methods	Randomised, not masked. Disease control = no new blisters for 4 weeks, prednisolone dose decreased gradually to 0.5 mg/kg at 3 months and 0.2 mg/kg at 6 months Follow‐up: 6 months (= treatment period)
Participants	100 participants with bullous pemphigoid confirmed by immunofluorescence studies Mean age in the prednisolone group was 75 years (17 males, 14 females), in the azathioprine plus prednisolone group 77 years (19 males, 17 females), and in the plasma exchange plus prednisolone group 75 years (14 males, 17 females). Disease severity was variable, mild to severe. Inclusion criteria: the diagnosis of BP required a skin biopsy demonstrating a subepidermal blister and deposits of immune reactants (IgG and/or C3) in a linear pattern along the basement‐membrane zone of the epidermis. Exclusion criteria People with localised disease and those who had received corticosteroids or immunosuppressive drugs in the month before hospitalisation Pregnancy Age below 18 years All medical conditions known or thought to increase the hazards of therapy with plasma exchange or azathioprine, such as cardiac failure, recent myocardial infarction, unstable angina, poor venous access on the arms, leukocyte counts below 4 x 109/L, platelet counts below 100 x 109/L, and abnormal values on liver tests
Interventions	A) 31/32 participants prednisolone 1 mg/kg/day B) 36/36 participants azathioprine plus prednisolone 1 mg/kg/day C) 31/32 participants plasma exchange plus prednisolone 1 mg/kg/day
Outcomes	Primary Disease control: no more than 1 new blister in the 4 weeks after starting treatment; these participants were followed up a further 6 months. Resolution of erythema and no more than minimal pruritus Secondary Numbers of participants with severe side effects or death
Notes	Trial stopped at interim period due to no appreciable benefit
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised. Quote: "According to pre‐established randomisation lists equilibrated in blocks of 3 for each centre" (Page 50).
Allocation concealment (selection bias)	Low risk	Quote: "After determining a patient's eligibility, the attending physician telephoned the co‐ordinator of the study, who assigned the patient to one of three treatment groups according to pre‐established randomisation lists, equilibrated in blocks of three for each centre." Thus, allocation concealment was performed.(Page 50)
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding
Blinding of outcome assessment (detection bias) All outcomes	High risk	No blinding
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Reasons for 2 dropouts not clear. Quote: "unavailable for follow‐up after having withdrawn their consent" (Page 51) (not clear if this was before or after starting treatment). Dropouts not included in the analysis.
Selective reporting (reporting bias)	Unclear risk	Controlled disease was stated to be no more than 1 new blister occurring at 4 weeks after starting treatment, resolution of erythema, and no more than minimal pruritis. Only the composite measure of controlled disease was reported (Table 11, Page 52).
Other bias	Unclear risk	Trial stopped early. Quote: "Our trial was interrupted after the interim analysis showed no appreciable benefit resulting from the addition of azathioprine or plasma exchange to prednisolone in the initial (at 4 weeks) and maintenance (at 6 months) treatments of BP" (Page 52).