Objective: In the absence of comparative trials a meta-analysis was performed to compare the efficacy and tolerability of the non-ergot derived dopamine agonists, pramipexole and ropinirole, in restless legs syndrome (RLS).
Methods: Frequentist fixed and random-effects models were pre-specified for the direct comparisons and a Bayesian approach for the indirect comparison. Efficacy outcomes included the mean change from baseline in the International RLS Study Group Rating Scale (IRLS) score and the percentage of responders on the clinical global impressions - improvement scale (CGI-I). Safety outcomes included the incidence of withdrawal and adverse events.
Results: The direct meta-analysis confirmed superior efficacy for both treatments versus placebo for the IRLS (pramipexole: -5.45; 95% CI: -7.70; -3.20; ropinirole: -3.16; 95% CI: -4.26; -2.05) and the CGI-I (pramipexole: OR=2.98; 95% CI: 2.08; 4.26; ropinirole: OR=1.99; 95% CI: 1.52; 2.60). Placebo comparisons showed a significantly higher incidence of nausea for pramipexole (p<0.01), whereas nausea, vomiting, dizziness, and somnolence were significantly higher for ropinirole (all p<0.01). The indirect comparison showed with a probability of > or = 95%, a superior reduction in the mean IRLS score (-2.33; 95% credibility interval [CrI]: -4.23; -0.41), higher CGI-I response rate (OR=1.50; 95% CrI: 0.97; 2.32) and significantly lower incidence of nausea, vomiting, and dizziness for pramipexole compared to ropinirole.
Conclusion: Differences in efficacy and tolerability favouring pramipexole over ropinirole can be observed. These findings should be further confirmed in head-to-head clinical trials.