Clinical Characteristics and Efficacy of Iron Treatment for Restless Legs Syndrome Patients with Very Low Ferritin Levels

Restless legs syndrome (RLS) is associated with dopaminergic dysfunction, and iron deficiency, manifesting as low ferritin. However, ferritin levels do not correlate well with demographic data. Based on the hypothesis that very low ferritin can accurately reflect clinical information, we herein described characteristics and treatment efficacy of RLS patients with ferritin levels under 15 ng/mL. We retrospectively reviewed 196 patients and collected clinical data. Twenty-one patients had ferritin levels under 15 ng/mL and were compared with those having ferritin levels over 15 ng/mL. The patients with very low ferritin levels were predominantly female, had earlier onset of symptoms, and showed a superior response to iron therapy. In conclusion, RLS patients with ferritin levels under 15 ng/mL showed distinct demographic features and treatment efficacy. Further studies on more patients with long-term follow-up are warranted to support this observation. Sleep Med Res 2018;9(2):118-123