FERRITIN: Augmentation in restless legs syndrome -low ferritin

Background and purpose: Augmentation is a major problem with dopaminergic therapy for restless legs syndrome (RLS), and predictors of augmentation have not yet been identified. We aimed to analyze the relationship between baseline ferritin level and occurrence of augmentation in a retrospective analysis of a prospective double-blind trial of cabergoline versus levodopa on augmentation in RLS.

Patients and methods: Patients who experienced augmentation were compared to patients who did not experience augmentation.

Results: Augmentation symptoms causing premature discontinuation from the study or which were tolerated (n = 36, ferritin: 85 + 59 ng/ml) were associated with lower levels of serum ferritin compared to patients without augmentation (n = 302, ferritin : 118 + 108 ng/ml, p = 0.0062).

Conclusions: Ferritin as a marker of iron storage may play an important role in the pathophysiology of RLS and may prove to be a biomarker for the development of augmentation under dopaminergic therapy.

Keywords: Restless legs syndrome; Augmentation; Dopaminergic therapy; Ferritin; Iron storage; Cabergoline; Levodopa

Corresponding author. Address: Paracelsus-Elena Klinik, Klinikstrasse 16, 34128 Kassel, Germany. Tel.: +49 561 6009 200; fax: +49 561 6009 126.