A double-blind placebo-controlled trial of antioxidant therapy in limited cutaneous systemic sclerosis

Herrick AL, Hollis S, Schofield D

Published in Clinical and Experimental Rheumatology

Methodology

Double-blind, placebo-controlled crossover trial of combined micronutrient antioxidants with allopurinol; analysed as a between-group comparison of the first 10-week period plus a within-group comparison of the two periods.

Key Findings

33 patients with limited cutaneous systemic sclerosis received a micronutrient antioxidant combination (selenium, beta-carotene, vitamin C, vitamin E, methionine) plus allopurinol or placebo. Over the first 10-week period there was no difference between groups in von Willebrand factor, thermographic rewarming after cold challenge, or patient-reported Raynaud symptoms, and no clinical benefit appeared in the 20-week crossover comparison either. Circulating antioxidant levels rose but markers of free-radical-mediated injury did not fall.

Conclusions

No clinical benefit could be demonstrated from active treatment. There are several possible explanations for this negative result, including the short duration of therapy. It is possible that antioxidant therapy, to be effective, needs to be given early in the SSc disease process, before the onset of irreversible tissue damage.

Limitations

Small sample (33 recruited) with a retrospectively detected carryover effect that forced a reanalysis; treatment period of 10-20 weeks may be too short, and patients had long-standing disease with possibly irreversible tissue damage.