Guillaume 1993.

Methods	Randomised, not blind 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 BP confirmed by IF studies
Interventions	31/32 participants prednisolone 1 mg/kg/day versus 36/36 participants azathioprine + prednisolone 1 mg/kg/day versus 31/32 participants plasma exchange + prednisolone 1 mg/kg/day.
Outcomes	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
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 center." (Page 50)
Allocation concealment (selection bias)	Unclear risk	Unclear. No details given about how the allocation was concealed from the study investigator. Quote: "After determining a patient's eligibility, the attending physician telephoned the study co‐ordinator who assigned the patient." (Page 50)
Blinding (performance bias and detection bias) All outcomes	High risk	The study was not blind. See "Treatment Groups", page 50. "Techinically difficult and theoretically debatable to perform 'sham' plasma exchanges".
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 Quote: "unavailable for follow‐up after having withdrawn their consent" (page 51) (not clear if this was before or after starting treatment).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 4 weeks after starting treatment, resolution of erythema, and no more than minimal pruritis. Only the composite measure of controlled disease was reported (Table 2, 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).