Is "normal" ferritin truly enough? Strong correlation between iron stores and RLS severity in patients with normal...

Area of Science:

• Neurology
• Hematology
• Clinical Research

Background:

• Idiopathic Restless Legs Syndrome (RLS) is a neurological disorder characterized by an urge to move the legs.
• Peripheral iron deficiency is implicated in RLS, but its role in patients with normal serum ferritin levels is less understood.

Purpose of the Study:

• To investigate the relationship between peripheral iron stores (serum ferritin) and symptom severity in drug-naive idiopathic RLS patients with normal ferritin levels.
• To identify independent predictors of RLS severity, including age, sex, comorbidities, and biochemical parameters.

Main Methods:

• Cross-sectional study of 113 drug-naive idiopathic RLS patients.
• Exclusion of patients with ferritin levels outside 22-322 μg/L or major confounding comorbidities.
• Assessment of RLS severity using the International Restless Legs Syndrome Rating Scale.
• Analysis of serum ferritin, magnesium, vitamin B12, vitamin D, folate, and hemoglobin.
• Multiple linear regression to determine independent predictors of RLS severity.

Main Results:

• Serum ferritin level (p < 0.001) and age (p = 0.001) were significant independent predictors of RLS severity.
• No independent effects of sex, hemoglobin, vitamin D, or other comorbidities on RLS severity were detected.
• A strong negative correlation was observed between ferritin levels and RLS symptom severity, even within the normal range.

Conclusions:

• Serum ferritin levels are a significant predictor of RLS symptom severity, even when within the normal laboratory reference range.
• Ferritin should be considered a continuous parameter in RLS management, not just a threshold value.
• Age is also an independent predictor of RLS severity in this patient population.