title: Frequent periodic leg movement during sleep is associated with left ventricular hypertrophy and adverse cardiovascular outcomes.
abstract: BACKGROUND
  Sleep disturbance caused by obstructive sleep apnea is recognized as a contributing factor to adverse cardiovascular outcomes. However, the effect of restless legs syndrome, another common cause of fragmented sleep, on cardiac structure, function, and long-term outcomes is not known. The aim of this study was to assess the effect of frequent leg movement during sleep on cardiac structure and outcomes in patients with restless legs syndrome.
  
  
  METHODS
  In our retrospective study, patients with restless legs syndrome referred for polysomnography were divided into those with frequent (periodic movement index > 35/hour) and infrequent (≤ 35/hour) leg movement during sleep. Long-term outcomes were determined using Kaplan-Meier and logistic regression models.
  
  
  RESULTS
  Of 584 patients, 47% had a periodic movement index > 35/hour. Despite similarly preserved left ventricular ejection fraction, the group with periodic movement index > 35/hour had significantly higher left ventricular mass and mass index, reflective of left ventricular hypertrophy (LVH). There were no significant baseline differences in the proportion of patients with hypertension, diabetes, hyperlipidemia, prior myocardial infarction, stroke or heart failure, or the use of antihypertensive medications between the groups. Patients with frequent periodic movement index were older, predominantly male, and had more prevalent coronary artery disease and atrial fibrillation. However, on multivariate analysis, periodic movement index > 35/hour remained the strongest predictor of LVH (odds ratio, 2.45; 95% confidence interval, 1.67-3.59; P < .001). Advanced age, female sex, and apnea-hypopnea index were other predictors of LVH. Patients with periodic movement index > 35/hour had significantly higher rates of heart failure and mortality over median 33-month follow-up.
  
  
  CONCLUSIONS
  Frequent periodic leg movement during sleep is an independent predictor of severe LVH and is associated with increased cardiovascular morbidity and mortality.
authors.affiliation: Center for Integrative Research on Cardiovascular Aging, Aurora University of Wisconsin Medical Group, Milwaukee, Wisconsin 53215, USA.
authors.forename: Mahek
authors.initials: M
authors.lastname: Mirza
authors.forename: Win-Kuang
authors.initials: WK
authors.lastname: Shen
authors.forename: Aamir
authors.initials: A
authors.lastname: Sofi
authors.forename: Ahad
authors.initials: A
authors.lastname: Jahangir
authors.forename: Naoyo
authors.initials: N
authors.lastname: Mori
authors.forename: A Jamil
authors.initials: AJ
authors.lastname: Tajik
authors.forename: Arshad
authors.initials: A
authors.lastname: Jahangir
mesh_terms: D000368:Aged; D016009:Chi-Square Distribution; D004452:Echocardiography / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011237:Predictive Value of Tests; D012148:Restless Legs Syndrome / Q000150:complications* / Q000503:physiopathology; D012189:Retrospective Studies; D012307:Risk Factors; D018709:Statistics, Nonparametric; D015996:Survival Rate