Racial differences in restless legs symptoms and serum ferritin in an incident dialysis patient cohort

Restless legs syndrome (RLS), a debilitating sleep disorder that is frequently reported by CKD patients on dialysis, may be more common in whites than in non-whites. Iron deficiency is associated with RLS, and serum ferritin is higher among African Americans compared to Caucasians in the general population. No prior studies have compared restless legs symptoms and serum ferritin levels of African-American and those of the Caucasian patients on dialysis.

In a multicenter observational study that included in-person interviews and medical chart review, we studied 210 patients who had recently started renal dialysis. Predictors of restless legs symptoms were examined in a multivariable logistic regression model.

African Americans had a reduced risk of restless legs complaint compared to Caucasian patients (OR, 0.44 [95% CI 0.21-0.93]; P=0.03). African-American patients were also less likely than Caucasian patients to have low serum ferritin values (<100 ng/ml), and among patients with serum ferritin≥100 ng/ml, the average serum ferritin of African-American patients was higher than that of Caucasian patients.

Further study of racial and iron status relationships could advance the understanding of RLS pathophysiology, and RLS is an important patient outcome to monitor, as revised anemia and iron protocols are implemented in the clinical setting.