A systematic review and meta-analysis of the effects of topical nitrates in the treatment of primary and secondary Raynaud's phenomenon.

Background: Multiple placebo-controlled trials have assessed locally applied topical nitrate preparations in treating Raynaud's phenomenon (RP).

Objectives: The objective of this meta-analysis was to assess the effects of local topical nitrates in primary and secondary RP with respect to a combined end point integrating parameters of digital blood flow and clinical severity.

Methods: A systematic review was performed using MEDLINE, Embase, and the Cochrane library. Only trials comparing locally applied topical nitrates with placebo comparators were included. Studies were appraised for bias by 2 independent reviewers.

Results: A total of 7 placebo-controlled trials including 346 patients were used in the meta-analysis; 4 trials used nitroglycerin ointments, 2 used the nitroglycerin gel vehicle MQX-503, and 1 used compounded nitrite. The meta-analysis results supported a moderate-to-large treatment effect in RP (standardized mean difference [SMD] = 0.70; 95% CI, 0.35-1.05; P < .0001). Subgroup analyses showed a large treatment effect in secondary RP (SMD = 0.95; 95% CI, 0.25-1.65; P = .008) and moderate effect in primary RP (SMD = 0.45; 95% CI, 0.05-0.85; P = .03).

Limitations: Limitations include the inclusion of multiple topical nitrate preparations and integration of different outcomes assessments.

Conclusion: Local topical nitrates have significant efficacy in the treatment of both primary and secondary RP.