Efficacy of oral iron in patients with restless legs syndrome and a low-normal ferritin: A randomized, double-blind, placebo-controlled study

Background and Purpose: Restless Legs Syndrome (RLS) is a primary disorder of sensation that affects sleep and has been associated with iron deficiency. The purpose of this study was to determine if symptomatic RLS patients with low-normal serum ferritin levels benefit from oral iron replacement. Patients and Methods: This was a randomized, placebo-controlled, double-blinded study. Eligible patients were randomized to oral iron therapy vs. appearance-matched placebo and followed over a 12 week period. Results: Baseline International Restless Leg Scale (IRLS) scores for the treatment (24.8 ± 5.72) and placebo (23.0 ± 5.03) groups were similar. Baseline ferritin levels for the treatment (40.6 ± 15.3 ng/ml) and placebo (36.7 ± 20.8 ng/ml) groups were also similar. After 12 weeks, IRLS scores decreased more in the treatment arm (10.3 ± 7.40) than in the placebo arm (1.14 ± 5.64), (p = 0.01). Ferritin levels increased more in the treatment arm (25.1 ± 20.3 ng/ml) than in the placebo arm (7.5 ± 13.7 ng/ml), (p = 0.04). We observed a nonsignificant trend toward improved quality of life in the treated patients, (p = 0.07). Conclusions: This is the first double-blinded, placebo-controlled study to demonstrate statistically significant improvement in RLS symptoms using oral iron therapy in patients with low-normal ferritin. The findings from this study suggest that additional larger randomized placebo-controlled trials of iron as treatment for patients with low-normal ferritin are warranted.