Clinical efficacy of ropinirole for restless legs syndrome is not affected by age at symptom onset

Objective: To determine whether clinical response to the dopamine agonist, ropinirole, in the treatment of primary restless legs syndrome (RLS), depends upon the age-at-onset of RLS symptoms. Methods: Pooled data from four 12-week, randomized, double-blind, placebo-controlled studies of ropinirole in patients with moderate-to-severe primary RLS were analyzed post hoc. The relationship between age-at-onset and response to treatment, based on change from the baseline International Restless Legs Syndrome Study Group (IRLSSG) rating scale (the International Restless Legs Scale [IRLS]) total score and the proportion of responders (rated 'much'/'very much' improved) on the Clinical Global Impression-Improvement (CGI-I) scale, was explored. Results: The range of age-at-onset of RLS symptoms was 2-75 years. No relationship was observed between the age-at-onset of RLS symptoms and baseline IRLS total score (correlation r = -0.06), and between dose administered at Week 12 last observation carried forward (LOCF) and age-at-onset (r = -0.04). The age-at-onset by treatment interaction was non-significant (P = 0.952 for the IRLS and P = 0.716 for the CGI-I scale), indicating there was no significant relationship between age-at-onset and the magnitude of ropinirole treatment effect. Conclusions: These data suggest that ropinirole provides effective relief of symptoms, regardless of age at RLS symptom onset.