High prevalence of restless legs syndrome among patients with fibromyalgia: a controlled cross-sectional study

To investigate the prevalence of restless legs syndrome (RLS) in fibromyalgia (FM) and determine the presence and amount of sleep disruption in FM patients with RLS. RLS and FM have been associated in uncontrolled studies using a variety of RLS definitions. We explored this relationship using a cross-sectional study design.

FM cases that met the American College of Rheumatology diagnostic criteria were recruited through an academic referral clinic and advertising. Pain- and fatigue-free controls were recruited from the Seattle metropolitan area. We enrolled 172 FM patients (mean age 50 years, 93% female) and 63 pain- and fatigue-free controls (mean age 41 years, 56% female). RLS was ascertained by a self-administered validated diagnostic interview.

The age- and gender-adjusted prevalence of RLS was higher in the FM group than the control group (33.0%; 95% CI: 25.9, 40.1 vs. 3.1%; 95% CI: 0.0, 7.4; p = 0.001). Likewise, the FM group was more likely to report RLS (OR = 11.7; 95% CI: 2.6, 53.0), even after adjusting for age and gender. The mean Pittsburgh Sleep Quality Index score was higher among FM patients with RLS than those without (11.8 vs. 9.9; p = 0.01) but subjective limb pain measures did not differ between these 2 groups.

There is a higher prevalence and odds of RLS in those with FM compared to controls. Clinicians should routinely query FM patients regarding RLS symptoms because treatment of RLS can potentially improve sleep and quality of life in these patients.