Relationship between prevalence and severity of restless legs syndrome and anemia in patients with systemic lupus erythematosus.

Abstract

Our aim was to evaluate the relationship between the prevalence and severity of restless legs syndrome (RLS) and the anemia in patients with systemic lupus erythematosus (SLE). This was a case-control study which was conducted at the rheumatology clinic of a university affiliated hospital, including 62 patients with SLE and 62 age- and sex-matched healthy controls. The patients were divided into two groups in terms of their hemoglobin levels. The criterion for anemia was hemoglobin level lower than 12 g/dL in females and 13 g/dL in males. Nineteen patients (30.6%) in the patient group were diagnosed with RLS, and International RLS Study Group Rating Scale (IRLSSG-RS) score was 10.7 ± 9.5 (median:10.0 [range:0.0-30.0]). Three subjects (4.8%) in the control group had RLS, and the IRLSSG-RS score was 0.7 ± 3.3 (median:0.0 [range:0.0-18.0]). The prevalence of RLS and the IRLSSG-RS score were higher in the patient group than those in the control group (P < 0.001). Ten SLE patients (50%) with anemia had RLS, and their IRLSSG-RS score was 14.5 ± 9.9 (median:21.0 [range:11.0-30.0]). Nine SLE patients (21.4%) without anemia had RLS and their IRLSSG-RS was 9.0 ± 8.9 (median:21.0 [range:11.0-24.0]). Significant differences were present in the prevalence of RLS and the IRLSSG-RS score between SLE patients with and without anemia (P = 0.024, P = 0.044, respectively). The present study demonstrated that the prevalence of RLS was higher in patients with SLE than that of the normal population. Results of this study also suggested that anemia was associated with higher frequency of and more severe RLS in patients with lupus.