The relationship between the frequency and severity of restless legs syndrome and anaemia in patients with ankylosing spondylitis

Background Background The study aims to determine the frequency of restless legs syndrome (RLS) in patients with ankylosing spondylitis (AS) and the relationship between the International Restless Legs Syndrome Study Group Rating Scale (IRLSSG-RS) score and anemia. Material and Methods It was a case-control study that included 106 patients with AS and 106 age- and sex-matched healthy controls in the rheumatology clinic of a training and research hospital. The patients were divided into two groups according to their hemoglobin levels. A hemoglobin level lower than 12 g/dL in women and less than 13 g/dL in men was the criterion for anemia. Results Although the frequency of RLS was higher in AS patients than in control groups, there was no significant difference in the IRLSSG-RS score between AS patients and control groups. 23 (57.5%) of the AS patients with anemia had RLS, and the IRLSSG-RS score was 21.3±5.7. Of the AS patients without anemia, 11 (16.7%) had RLS, and the IRLSSG-RS score was 15±6. Statistically significant differences between AS patients with and without anemia regarding RLS frequency and IRLSSG-RS score were found. The IRLSSG-RS scores of AS patients were negatively correlated with serum iron and hemoglobin level. Conclusions Patients with AS had a higher RLS frequency than the control group; AS patients with anemia had a higher RLS and IRLSSG-RS score than AS patients without anemia. Also, a negative and significant correlation was found between the IRLSS-RS score and serum iron and hemoglobin levels in AS patients.