Locally applied topical nitrates effective for Raynaud’s phenomenon
Locally applied topical nitrates appear to be significantly effective in the treatment of primary and secondary Raynaud’s phenomenon (RP), according to a recent meta-analysis.
Pooled analysis from seven studies showed that topical nitrates had a significant moderate-to-large treatment effect on RP relative to placebo (standardized mean difference [SMD], 0.70; 95 percent CI, 0.36–1.05; p=0.00006). Significant heterogeneity was observed in this dataset.
Subsequent subgroup analyses showed that this effect was more pronounced in secondary (SMD, 0.95; 0.25–1.65; p=0.008) than in primary (SMD, 0.45; 0.05–0.85; p=0.0e) RP, but nevertheless remained significant in both cases. The secondary, but not the primary, RP group showed significant heterogeneity.
A post-hoc random effects meta-regression analysis used MQX-503, an alternative nitroglycerin gel vehicle, as a covariate and showed that it accounted for 73 percent of the heterogeneity in the main study group and 100 percent of the heterogeneity in the secondary RP subgroup.
MQX-503 yielded smaller effect sizes in the main study group (SMD, 0.36; 0.13–0.60; p=0.05) and secondary RP subgroup (SMD, 0.38; 0.09–0.67; p=0.01). This may be due to the different efficacies of the vehicle or the variations in trial designs, said researchers.
“Future comparative clinical trials may clarify whether differences between vehicles are attributable to a lower relative efficacy of MQX-503 vehicle or other factors,” they added.
For the present meta-analysis, researchers accessed the databases of the Cochrane library, Embase and Medline for trials that compared the efficacy of locally applied topical nitrates with placebo for RP. Efficacy was measured as subjective clinical improvements or objective improvement in digital blood flow.