PURPOSE: Restless legs syndrome (RLS) is characterized by an irresistible urge to move the legs during rest or sleep. Female cases appear to outnumber male cases. Although pramipexole has been found beneficial, there remains the question of whether females and males respond differently.
METHODS: Data were analyzed from three double-blind, placebo-controlled clinical trials of 3, 6, and 12 weeks. Pramipexole doses were 0.125 to 0.75 mg/d. Patients met all criteria of the International RLS Study Group, including a baseline score >15 on the Group's RLS severity scale (IRLS). Efficacy was assessed by IRLS, Clinical Global Impressions –Global Improvement scale (CGI-I), and Patient Global Impression scale (PGI). The change in IRLS score from baseline was analyzed by analysis of covariance, the CGI-I and PGI responder rates by Cochran-Mantel-Haenszel test.
RESULTS: Among a total of 512 females, 363 (70.9%) received pramipexole and 149 (29.1%) received placebo. Among 272 males, 201 (73.9%) received pramipexole and 71 (26.1%) received placebo. Across the trials, the mean baseline IRLS score was 22.8 to 25.5 in females and 22.5 to 24.4 in males, representing moderate to severe RLS. For females, the mean IRLS change, adjusted for baseline and age, ranged from −12.2 to −15.0 for pramipexole and from –5.9 to –10.9 for placebo (p<0.0001 to p=0.0220, depending on trial). For males, the range was –11.1 to –15.2 for pramipexole, compared with –4.1 to –6.4 for placebo (p<0.0001 to p=0.0431). On CGI-I, 70.1% of female and 66.8% of male pramipexole recipients were responders (“much” or “very much” improved), compared with 45.6% and 30.0%, respectively, for placebo recipients (both p<0.0001). On PGI, 63.4% of female and 57.2% of male pramipexole recipients were responders (“much” or “very much” better), compared with 43.0% and 25.4% for placebo (both p<0.0001).
CONCLUSION: By IRLS, CGI-I, and PGI, pramipexole provided similar, significant benefit for both females and males with RLS.
CLINICAL IMPLICATIONS: Pramipexole is an effective RLS therapy in both sexes.
DISCLOSURE: Eric Lainey, No Product/Research Disclosure Information; Grant monies (from industry related sources) This study was supported by Boehringer Ingelheim International GmbH.; Employee Eric Lainey, MD; Stefan Albrecht, MD; and Juergen Koester, PhD are employees of Boehringer Ingelheim.