Kinney 1982.

Methods	Double‐blind randomized placebo‐controlled trial Cross‐over design
Participants	16 patients ‐ 10 progressive systemic sclerosis, 2 mixed connective tissue disease, 2 with systemic lupus erythematosus, 2 with Raynaud's disease 2 dropouts
Interventions	No vasoactive drug other than the one being tested (verapamil) All study participants non‐smokers except for 1 participant who continued to smoke 4 cigarettes a day throughout the duration of the experiment Concomitant medications not changed during this study Verapamil administered orally for 3 weeks followed by increased dosage for 3 weeks Last 6 weeks of study ‐ treatment groups crossed over Total study duration 12 weeks
Outcomes	Participants interviewed and examined at start of the study and every 3 weeks thereafter Diary analysis to ascertain whether participants had at least 1 episode of Raynaud's phenomenon on a given day Pulse volume, total blood flow in the tip of the finger, skin temperature, and cold pressor testing measured
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"computer‐generated randomization schedule"
Allocation concealment (selection bias)	Low risk	Likely occurred on the basis of computer generation
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"The study was double‐blinded." "Placebo‐treated patients received equivalent numbers of capsules."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Participant diary used to record subjective assessments and to check compliance
Incomplete outcome data (attrition bias) All outcomes	Low risk	2/16 participants with completed diary excluded from analysis
Selective reporting (reporting bias)	Low risk	None detected
Other bias	Unclear risk	Evidence insufficient for judgement of risk