Restless legs syndrome in 218 patients: associated disorders

Abstract

Background: Restless legs syndrome (RLS) is a disorder characterized by disagreeable sensations in the legs that occur at rest and are relieved by movement. These symptoms, which are worse at night, may result in sleep onset or sleep maintenance insomnia. Most patients are found on polysomnography (PSG) to have periodic limb movements in sleep (PLMS). The disorder, idiopathic in most cases, may be sometimes associated with specific disorders.

Methods: Using the Province of Manitoba Health database, we compared the diagnoses made in the 5 years prior to sleep laboratory evaluation of 218 patients (103 men and 115 women) with RLS and 872 matched control subjects from the general population.

Results: We found that 43.7% of male RLS patients vs. 10.4% of male controls and 46.1% of female RLS patients vs. 22.8% of female controls had been diagnosed as having psychological/psychiatric (most often depression) disorders (P<0.05). Extrapyramidal disease or movement disorders were previously diagnosed in 17.5% of male RLS patients vs. 0.2% of male controls and in 23.5% of female patients vs. 0.2% of female controls (P<0.05). Many patients had been previously diagnosed with disorders of the musculoskeletal system: 35.9% of male patients vs. 22.8% of male controls and 49.6% of female RLS patients vs. 23.3% of female controls had been diagnosed as having diseases of joints (male; P=ns, female; P<0.05). Disorders of the back were also more frequently diagnosed in RLS patients: 21.4% of male patients vs. 13.1% of male controls and 38.3% of female patients vs. 15.0% of female controls (male; P=ns, female; P<0.05).

Conclusions: We conclude that RLS patients are much more likely to have previously been diagnosed with extrapyramidal disorders, musculoskeletal disorders, depression, and painful conditions such as joint and back disorders.

Introduction

Restless legs syndrome (RLS), a very common disorder, is characterized by discomfort in the legs described as creeping, crawling, tingling, or painful [1]. The unpleasant sensations are precipitated by rest and relieved by activity. These symptoms are worse at bedtime and thus RLS patients complain of sleep disturbance, especially insomnia. Most RLS patients have periodic limb movements in sleep (PLMS) documented by polysomnography (PSG). These findings are diagnostic of periodic limb movement disorder (PLMD) [2]. It may be that RLS is simply a manifestation or a presentation of PLMD, and that the separation into distinct diagnostic entities may not be appropriate. It is likely that RLS may be present in 10–15% of the population [3]. The physiological mechanisms causing RLS are unknown. The disorder, idiopathic in most cases, has been associated with iron deficiency [4], polyneuropathy [5], rheumatoid arthritis [6], and hemodialysis [7], [8]. Patients may become symptomatic at any age and have been reported to wait a mean of 2 years after first seeking medical attention before a diagnosis is made [9]. In an attempt to shed light on the reason for delayed diagnosis, and to confirm that RLS was more common in groups of patients with certain diseases, we compared the diagnoses patients had received in the 5 years prior to sleep laboratory evaluation to a matched control group from the general population.