Restless legs syndrome is prevalent in adults with cystic fibrosis and impacts sleep quality

Background: Restless legs syndrome (RLS) is a sensorimotor disorder that is prevalent in chronic inflammatory conditions. RLS prevalence, risk factors, and impact on sleep in CF have not been extensively characterized to date. Methods: An initial cohort was examined, including 75 persons with CF (PwCF) and 75 control subjects, to look at the prevalence and severity of RLS. A second validation cohort of 191 PwCF was then enrolled from two CF centers to examine risk factors for RLS. A diagnosis of RLS was made according to the International RLS Study Group (IRLSSG) criteria. Sleep quality was identified using the Pittsburgh sleep quality index (PSQI). Epworth sleepiness scale (ESS) was used to measure daytime sleepiness. We then analyzed laboratory and clinical risk factors and sleep symptoms for potential risk factors for RLS. Results: In the initial cohort, 36 % of PwCF had RLS, and 9 % of these had significant RLS. In contrast, only 15 % of controls had RLS, and none had significant RLS. In the second larger validation cohort with 191 subjects, a comparable prevalence of RLS was identified. Higher hemoglobin A1c, use of SSRI/SNRI medications, worse PSQI and ESS sleep quality scores, lower lung function, and higher antibiotic usage were significantly associated with a diagnosis of RLS. By multivariate multinominal logistic regression analysis, higher HbA1c and worse PSQI global sleep quality scores were independent predictors of significant RLS. Conclusions: RLS is highly prevalent in CF. Higher HbA1c and poor sleep quality, signified by higher PSQI, were each independent predictors of RLS.