Results from a Health Professionals Follow-up Study analysis support an association.

To examine the controversial notion that restless legs syndrome (RLS) is associated with increased mortality, researchers tracked mortality among 18,425 participants in the Health Professionals Follow-up Study (HPFS) who answered a standardized questionnaire about the potential presence of RLS. Patients with diabetes, arthritis, or renal failure were excluded. The investigators documented deaths comprehensively using vital statistics, the National Death Index, family reports, and the postal system.

A total of 2765 deaths occurred between 2002 and 2010. After adjustment for age, RLS was associated with a significant increase in mortality (hazard ratio [HR], 1.39). The association was mildly weakened after adjustment for factors such as body-mass index, lifestyle, other chronic diseases, amount of sleep, and other sleep-related disorders (adjusted HR, 1.30). After excluding other chronic diseases associated with RLS (e.g., Parkinson disease), the association remained significant (adjusted HR, 1.92). Age, weight, short sleep duration, smoking, poor exercise, and a less healthy diet did not affect the association. The study did not include blood testing for iron deficiency.

Comment: Restless legs syndrome affects an estimated 5% to 10% of the population. Because of the association between RLS and chronic conditions such as renal disease, disentangling the mortality risk of RLS has been challenging. Strengths of the current study include accounting for all potential comorbidities such as diabetes, cardiovascular disease, and kidney disease, and establishment of the RLS diagnosis through the use of standardized questions. Not only was there an increased mortality with RLS in general, but this increased mortality occurred more commonly when there was concomitant respiratory dysfunction, endocrine disease, nutritional issues, or presence of metabolic disease or an immunologic disorder. Although observational studies do not prove causality, clinicians should be aware of the increased mortality risk in any patient presenting with RLS-type symptoms. This study was limited by the lack of information on use of dopaminergic medication, which is the best treatment for RLS. Neurologists and primary care doctors should to work together when treating RLS patients. Treating primary RLS symptoms and addressing sleep, blood pressure, cardiovascular, and other comorbidities could be helpful. However, we do not yet understand how to modify the increased mortality risk in patients with RLS.

Source: Journal Watch Neurology