Association between restless legs syndrome and migraine Ping-Kun Chen, 1,2,3 Jong-Ling Fuh, 4,5 Shih-Pin Chen, 4,5 Shuu-Jiun Wang 4,5 ABSTRACT Background An association between restless legs syndrome and migraine has been reported recently. The clinical correlates and impact of comorbidity of restless legs syndrome (RLS) are not fully described in patients with migraine. Objectives To investigate the frequency of RLS among different primary headache disorders, and its impact and clinical correlates in migraine patients. Methods Consecutive patients with migraine, tension- type headache (TTH) and cluster headache (CH) were recruited in a headache clinic. Each patient completed the Migraine Disability Assessment (MIDAS) questionnaire, Hospital Anxiety and Depression Scale (HADS), Pittsburgh Sleep Quality Index (PSQI) and International RLS Study Group (IRLSSG) Rating Scale. RLS was diagnosed using the IRLSSG criteria. Results A total of 1041 patients (migraine 772, TTH 218, CH 51) completed the study. The frequencies of RLS in patients with migraine (11.4%) was higher than in those with TTH (4.6%) or CH (2.0%) (p¼0.002). In migraine patients, comorbidity with RLS was associated with higher frequencies of photophobia, phonophobia, exacerbation due to physical activities, vertigo, dizziness, tinnitus and neck pain, and higher mean scores of MIDAS and HADS. Migraine patients with RLS had a poorer sleep quality (Pittsburgh Sleep Quality Index score 11.164.1 vs 8.964.0, p<0.001) than those without. Conclusion An association between migraine and RLS among different primary headache disorders is demonstrated. Comorbid RLS in migraine patients worsened sleep quality. A shared underlying mechanism may account for the correlates between migraine features and comorbid RLS. INTRODUCTION Restless legs syndrome (RLS) is a sensorimotor disorder, which is characterised by uncomfortable sensations in the legs, especially at rest or at bed time, and relieved by voluntary movement. 1 The prevalence of RLS is 5e10% in Western count- ries 2e4 but only 0.6e3.9% in Asians. 5e7 Women and older populations have a higher prevalence. RLS has been found to be associated with a variety of medical and psychiatric conditions, and is diag- nosed in conjunction with other sleep disorders. 8 It has substantial impacts on sleep as well as on health-related quality of life. 9 10 Recently, RLS has been found to be a risk factor for cardiovascular diseases. 11 In recent years, several studies identified a higher prevalence of RLS in patients with migraine. 12e14 Whether RLS is also associated with other primary headache disorders is uncertain. Migraine has been reported to have an association with poor sleep qual- ity, especially in those with chronic migraine. 15 16 The inter-relationship among comorbid RLS, sleep disturbance and headache clinical profiles in patients with migraine has not been fully inves- tigated. 14 The specific goals of this paper are: (1) to examine the frequency of RLS in Taiwanese patients with three major primary headache disor- ders: migraine, tension-type headache (TTH) and cluster headache (CH); and (2) to explore the clin- ical correlates of comorbid RLS and its impact on sleep in patients with migraine. METHODS We prospectively enrolled consecutive patients aged $18 years with three primary headache disorders, that is, migraine, TTH or CH, who visited the headache clinic of Taipei Veterans General Hospital (VGH) from January 2008 to May 2009. Taipei- VGH is a 2909-bed medical centre serving both veterans and non-veteran citizens. In Taiwan, the government-run, single payer insurance system is supported by the National Health Insurance Program launched in 1995. The population coverage rate is more than 96%. Taiwan does not have a structured or formal system of medical referral. Patients have the right to choose any hospital or physician they wish, regardless of the severity of their illness. Fewer than 4% of the patients who arrive at our headache clinic are referred. Diagnoses of headache disorders were based on the International Classification of Headache Disorders, 2nd edition (ICHD-II). 17 For study inclusion, patients had to fulfil the diagnostic criteria for migraine (coded 1.1, 1.2, 1.5.1, 1.6), TTH (coded 2.2, 2.3), or CH (code 3.1). If patients had both migraine and TTH, they were classified into the migraine group. We excluded patients with secondary headache disorders except for medication overuse headache. Migraine was further classified into chronic migraine and episodic migraine. Chronic migraine was defined if headache, of either tension-type and/or migraine quality, occurs on $15 days per month and migraine frequency $8 days per month lasting for 3 months; other patients were diagnosed as episodic migraine. 18 This study protocol was approved by the Institu- tional Review Board at Taipei-VGH. Patients signed informed consent before entering the study. STUDY ASSESSMENT We recorded demographic data including body weight and height, and headache profiles such as head- ache intensity, frequency, locations, characteristics, See editorial Commentary, p 473 1 Department of Neurology, Lin-Shin Hospital, Taichung, Taiwan 2 Graduate Institute of Clinical Medicine Science, China Medical University, Taichung, Taiwan 3 Department of Health Care Administration, Central Taiwan University of Science and Technology, Taichung, Taiwan 4 Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan 5 National Yang-Ming University School of Medicine, Taipei, Taiwan Correspondence to Dr Shuu-Jiun Wang, Neurological Institute, Taipei Veterans General Hospital, Taipei 11217, Taiwan; sjwang@vghtpe.gov.tw Received 13 August 2009 Revised 17 October 2009 Accepted 19 October 2009 524 J Neurol Neurosurg Psychiatry 2010;81:524e528. doi:10.1136/jnnp.2009.191684 Research paper