[Note: The ferritin test is used to determine iron deficiency (low ferritin) or overload (high ferritin).]
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 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+/-15.3ng/ml) and placebo (36.7+/-20.8ng/ml) groups were also similar.
After 12 weeks, International Restless Leg Scale (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+/-20.3ng/ml) than in the placebo arm (7.5+/-13.7ng/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.
Source: Sleep Medicine, Feb 16, 2009. PMID: 19230757, by Wang J, O'Reilly B, Venkataraman R, Mysliwiec V, Mysliwiec A. Department of Medicine, Madigan Army Medical Center, Tacoma, Washington, USA. [E-mail: firstname.lastname@example.org]