The effect of silver fibre gloves on Raynaud's phenomenon in patients with systemic sclerosis: a double-blind randomized crossover trial

Objectives. Silver fibre gloves transport heat from the palm to the fingers, possibly reducing the burden of RP in SSc patients. We aim to evaluate the clinical efficiency of this intervention. Methods. A multicentre, double-blind, randomized trial was performed, accounting for interindividual differences and external factors using a crossover design. Patients were randomized in two groups: group 1 wore 8% silver fibre gloves in period 1 and normal gloves in period 2 and group 2 vice versa. Each period lasted 6 weeks. The primary outcome was the Raynaud Condition Score (RCS) over time (minimal clinical important difference 1.4), assessed three times per week using an online questionnaire. Secondary outcomes included vascular complications and Scleroderma-Health Assessment Questionnaire (SHAQ). Outcomes were evaluated before unblinding using linear mixed models. Results. A total of 85 SSc patients were included, with 76 completing the study. The mean RCS during 2 weeks before the study (i.e. without gloves) was 6.4 (s.D. 1.6). Both with silver fibre gloves and normal gloves the mean RCS decreased to 3.9 (s.D. 2.3) with a similar course over time. There was no difference in mean RCS over time between the type of gloves [beta=0.067 (95% CI -0.006, 0.19)]. Of secondary outcomes, total SHAQ [beta=0.036 (95% CI 0.026, 0.046)] was slightly higher with silver fibre gloves, which is clinically irrelevant. Three patients developed new digital ulcers with normal gloves vs one patient with silver fibre gloves [odds ratio 3.2 (95% CI 0.32, 31.1)]. Conclusions. Wearing gloves in SSc patients clearly decreases the RP burden. Our results do not support the hypothesis that increased heat transport of 8% silver fibre gloves is associated with less disease burden as measured in this study by the RCS compared with normal gloves.