Kahan 1985b.

Methods	Double‐blind randomized placebo‐controlled prospective study Cross‐over design
Participants	N = 16 patients ‐ 14 women and 2 men Mean age 41.5 years, range 18 to 57 7 with systemic sclerosis, 2 rheumatoid arthritis, 1 systemic lupus erythematosus, 6 idiopathic Raynaud's phenomenon Mean disease duration 12.8 years No dropouts
Interventions	Each participant given placebo in a single‐blind fashion for 1 week Participants randomized to receive placebo or diltiazem in a double‐blind fashion for 2 weeks, then crossed over for the last 2 weeks Total study duration 5 weeks
Outcomes	Participant diary used to record frequency, severity, and number of attacks Participants asked about overall effectiveness of treatments Side effects recorded
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"randomized double cross‐over protocol" Evidence insufficient for judgement of risk
Allocation concealment (selection bias)	Unclear risk	Evidence insufficient for judgement of risk
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind cross‐over study
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"Patients kept a record to attacks...severity, and effectiveness."
Incomplete outcome data (attrition bias) All outcomes	Low risk	None detected
Selective reporting (reporting bias)	Low risk	None detected
Other bias	Unclear risk	No mention of a washout period between cross‐over phases