Association of incident restless legs syndrome with outcomes in a large cohort of US veterans

Dopamine agonists and risk of lung cancer in patients with restless legs syndrome

PURPOSE

To examine the association between long-term use of dopamine agonists (DAs) and the risk of lung cancer in patients with restless legs syndrome (RLS).

METHODS

We conducted a retrospective cohort study using Optum Clinformatics® database. We included adults ≥40 years diagnosed with RLS during the study period (1/2006-12/2016). Follow-up started with the first RLS diagnosis and ended on the earliest of: incident diagnosis of lung cancer, end of enrollment in the database or end of the study period. The exposure of interest was cumulative duration of DAs use, measured in a time-varying manner. We constructed a multivariable Cox regression model to estimate HRs and 95% CIs for the association between lung cancer and cumulative durations of DA use, adjusting for potential confounding variables.

RESULTS

We identified 295 042 patients with a diagnosis of RLS. The mean age of the cohort was 62.9; 66.6% were women and 82.3% were white. The prevalence of any DA exposure was 40.3%. Compared to the reference group (no use and ≤1 year), the crude HRs for lung cancer were 1.16 (95% CI 0.99-1.36) and 1.14 (95% CI 0.86-1.51) for 1-3 years and >3 years of cumulative DA use, respectively. The adjusted HR for lung cancer was 1.05 (95% CI 0.88-1.25) for 1-3 years and 1.02 (95% CI 0.76-1.37) for >3 years of cumulative DA use, respectively.

CONCLUSIONS

At typical doses for the clinical management of RLS, long-term DA use was not associated with risk of lung cancer.

Sleep Disorders and Coronary Artery Disease

A sufficient amount and quality sleep is vital components for maintaining optimal physical wellbeing, cognition, and cardiovascular health. Normal sleep provides us with a low physiological stress that promotes overall cardiovascular health. Sleep disorders are common, and often goes undiagnosed. Patients with sleep disorders, commonly suffer from poor quality of life due to the poor quality of their sleep. They are associated with adverse effects on cardiovascular health, such as coronary artery disease. Sleep disorders discussed in this review article include sleep-disordered breathing (obstructive sleep apnea and central sleep apnea), insomnia and restless leg syndrome. Sleep disorders primarily have four acute adverse cardiovascular consequences. First, intermittent hypoxemia-reoxygenation in arterial blood along with PCO 2 fluctuation; second is excessive arousals; third, decreased parasympathetic and increased sympathetic tone; fourth being the large pressure swings in the intrathoracic cavity. This review focuses on classifications, and prevalence of the three major classes of sleep disorders, and the evidence to date on the association between these sleep disorders and coronary artery disease.

Genetic evidence for a potential causal relationship between insomnia symptoms and suicidal behavior: a Mendelian randomization study

Insomnia and restless leg syndrome (RLS) are associated with increased risk for suicidal behavior (SB), which is often comorbid with mood or thought disorders; however, it is unclear whether these relationships are causal. We performed a two-sample Mendelian randomization study using summary-level genetic associations with insomnia symptoms and RLS against the outcomes of risk of major depressive disorder (MDD), bipolar disorder (BP), schizophrenia (SCZ), and SB. The inverse-variance weighted method was used in the main analysis. We performed replication and sensitivity analyses to examine the robustness of the results. We identified outcome cohorts for MDD (n = 170,756 cases/329,443 controls), BP (n = 20,352/31,358), SCZ (n = 69,369/236,642), SB-Cohort-2019 (n = 6569/14,996 all with MDD, BP or SCZ; and SB within individual disease categories), and SB-Cohort-2020 (n = 29,782/519,961). Genetically proxied liability to insomnia symptoms significantly associated with increased risk of MDD (odds ratio (OR) = 1.23, 95% confidence interval (CI) = 1.2-1.26, P = 1.37 × 10^-61), BP (OR = 1.15, 95% CI = 1.07-1.23, P = 5.11 × 10^-5), SB-Cohort-2019 (OR = 1.17, 95% CI = 1.07-1.27, P = 2.30 × 10^-4), SB-Cohort-2019 in depressed patients (OR = 1.34, 95% CI = 1.16-1.54, P = 5.97 × 10^-5), and SB-Cohort-2020 (OR = 1.24, 95% CI = 1.18-1.3, P = 1.47 × 10^-18). Genetically proxied liability to RLS did not significantly influence the risk of any of the outcomes (all corrected P > 0.05). Results were replicated for insomnia with MDD and SB in Mass General Brigham Biobank and were consistent in multiple lines of sensitivity analyses. In conclusion, human genetic evidence supports for the first time a potentially independent and causal effect of insomnia on SB and encourages further clinical investigation of treatment of insomnia for prevention or treatment of SB.

Prevalence of restless legs syndrome in people with diabetes mellitus: A pooling analysis of observational studies

BACKGROUND

Diabetes mellitus (DM) is associated with different clinical complications. The aim of this study was to explore the prevalence of RLS in people with diabetes mellitus and compare the risk of restless leg syndrome (RLS) between diabetic and non-diabetic population.

METHODS

We searched for studies of RLS prevalence in DM through PubMed, Embase, and Web of Science. Two authors independently completed the literature screening, data extraction, and bias risk assessment of eligible studies. All observational studies that assessed the prevalence or risk of RLS in DM were included, where the diagnosis of RLS was based on the International Restless Legs Syndrome Study Group (IRLSSG). Percentages, odds ratio (OR) with 95% confidence intervals (CI) were used to assess pooled estimates of RLS prevalence and risk based on random-effects models. Newcastle-Ottawa-scale (NOS) or a modified NOS were used to evaluate the quality of studies.

FINDINGS

A total of 42 studies, including 835,986 participants, met the eligibility criteria for the meta-analysis. Among them, 30 studies were included in meta-analysis to analyze the prevalence of RLS. A second meta-analysis was conducted using 31 studies to determine RLS risk between diabetes and non-diabetes. The results indicate that between 25% (95% confidence interval 21%-29%) of people with diabetes showed signs of RLS, and people with diabetes had an increased risk of developing RLS compare to people without diabetes (OR 1.98, 95%CI 1.66- 2.34, p < 0.001). However, the available evidence was limited due to potential risk of bias and variability between studies (I² >75%), all of observational design.

INTERPRETATION

Our study suggests that the prevalence and risk of RLS might be higher in DM patients than in non-diabetes population. However, given limitations in the analysis and study design, the findings need to be corroborated in future studies.

FUNDING

This work was supported by the Basic Conditions Platform Construction Project of Sichuan Science and Technology Department (2019JDPT0015), and the "1・3・5 project for disciplines of excellence, West China Hospital, Sichuan University" (ZYJC18003).

The prevalence and potential aetiological factors associated with restless legs syndrome in patients with chronic kidney disease: a cross-sectional study

BACKGROUND

There is limited understanding of aetiological factors of and treatment options for restless leg syndrome (RLS) in patients with chronic kidney disease (CKD). This study aimed to estimate the prevalence of RLS in CKD patients and identify factors that may contribute to RLS.

METHODS

A questionnaire-based cross-sectional study of patients with CKD stage 4 (CKD 4), pre-dialysis stage 5 (CKD-5ND) and haemodialysis-dependent stage 5 (CKD-5D) was conducted. Eligible patients were enrolled from the local dialysis units and renal clinics. The International RLS Study Group rating scale was used to establish the diagnosis of RLS and quantify its severity.

RESULTS

212 patients with CKD 4 (n = 92), CKD-5ND (n = 14) and CKD-5D (n = 106) were included. The overall prevalence of RLS was 32.1%. Women had a significantly higher odds of having RLS despite adjustment for age, diabetes, cardiovascular disease and whether patients were on dialysis (odds ratio 2.8 [95% confidence intervals 1.5-5.2]). In pre-dialysis groups, patients with RLS had significantly higher serum ferritin (323.9 [SD 338.1] vs 177.5 [SD 178.5] µg/L, p = 0.020) compared to non-RLS patients. In dialysis patients (CKD-5D), those with RLS had significantly higher total white cell (8.0 [SD 3.5] vs 6.8 [SD 1.9] × 10⁹/L, p = 0.026) and neutrophil (6.4 [SD 3.9] vs 4.6 [SD1.7] × 10⁹/L, p = 0.002) counts compared to patients without RLS.

CONCLUSION

RLS remains a significant problem in patients with CKD and may be related to underlying inflammation. Targeting this pathway may be useful. Prevalence of RLS, diagnosed using validated measures, is higher than previous reports.

TRIAL REGISTRATION

N/A (the current study is not a trial).

The Long-Term Psychiatric and Cardiovascular Morbidity and Mortality of Restless Legs Syndrome and Periodic Limb Movements of Sleep

Restless legs syndrome (RLS) is a sensory-motor neurological disorder that is associated with high levels of distress and sleep disturbance. Cross-sectional and longitudinal evidence suggests that individuals suffering from RLS may be at an increased risk of certain psychiatric illnesses and cardiovascular diseases. There also is evidence for increased mortality rates in RLS patients, although contrasting results do exist. Periodic limb movements of sleep (PLMS), repetitive leg movement observed in most RLS patients, and sleep disturbance may mediate the relationship between RLS and long-term morbidity. This article summarizes the literature investigating the potential consequences of both RLS and PLMS.

Cardiac Involvement in Movement Disorders

Background

Several conditions represented mainly by movement disorders are associated with cardiac disease, which can be overlooked in clinical practice in the context of a prominent primary neurological disorder.

Objectives

To review neurological conditions that combine movement disorders and primary cardiac involvement.

Methods

A comprehensive and structured literature search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria was conducted to identify disorders combining movement disorders and cardiac disease.

Results

Some movement disorders are commonly or prominently associated with cardiac disease. Neurological and cardiac symptoms may share underlying physiopathological mechanisms in diseases, such as Friedreich's ataxia and Wilson's disease, and in certain metabolic disorders, including Refsum disease, Gaucher disease, a congenital disorder of glycosylation, or cerebrotendinous xanthomatosis. In certain conditions, such as Sydenham's chorea or dilated cardiomyopathy with ataxia syndrome (ATX-DNAJC19), heart involvement can present early in the course of disease, whereas in others such as Friedreich's ataxia or Refsum disease, cardiac symptoms tend to present in later stages. In another 68 acquired or inherited conditions, cardiac involvement or movement disorders are seldom reported.

Conclusions

As cardiac disease is part of the phenotypic spectrum of several movement disorders, heart involvement should be carefully investigated and increased awareness of this association encouraged as it may represent a leading cause of morbidity and mortality.

Sleep Disorders in Stroke: An Update on Management

Stroke is a leading cause of disability and mortality all over the world. Due to an aging population, the incidence of stroke is rising significantly, which has led to devastating consequences for patients. In addition to traditional risk factors such as age, hypertension, hyperlipidemia, diabetes and atrial fibrillation, sleep disorders, as independent modifiable risk factors for stroke, have been highlighted increasingly. In this review, we provide an overview of common types of current sleep disturbances in cerebrovascular diseases, including insomnia, hypersomnia, breathing-related sleep disorders, and parasomnias. Moreover, evidence-based clinical therapeutic strategies and pitfalls of specific sleep disorders after stroke are discussed. We also review the neurobiological mechanisms of these treatments as well as their effects on stroke. Since depression after stroke is so prevalent and closely related to sleep disorders, treatments of post-stroke depression are also briefly mentioned in this review article.

Grey matter alterations in restless legs syndrome: A coordinate-based meta-analysis

Brain structural abnormalities in idiopathic restless legs syndrome have long been debated. Voxel-based morphometry is an objective structural magnetic resonance imaging technique to investigate regional grey matter volume or density differences between groups. In the last decade, voxel-based morphometry studies have exhibited inconsistent and conflicting findings regarding the presence and localization of brain grey matter alterations in restless legs syndrome. We therefore conducted a coordinate-based meta-analysis to quantitatively examine whether there were consistent grey matter findings in restless legs syndrome using the latest algorithms, seed-based d mapping with permutation of subject images. We included 12 voxel-based morphometry studies (13 datasets, 375 patients and 385 healthy controls). Our coordinate-based meta-analysis did not identify evidence of consistent grey matter alterations in restless legs syndrome. Grey matter alterations via voxel-based morphometry analysis are not therefore recommended to be used as a reliable surrogate neuroimaging marker for restless legs syndrome. This lack of consistency may be attributed to differences in sample size, genetics, gender distribution and age at onset, clinical heterogeneity (clinical course, anatomical distribution of symptoms, disease severity, disease duration, abnormal sensory profiles and comorbidity), and variations in imaging acquisition, data processing and statistical strategies. Longitudinal studies with multimodal neuroimaging techniques are needed to determine whether structural changes are dynamic and secondary to functional abnormalities.

Treating Restless Legs Syndrome Was Associated With Low Risk of Cardiovascular Disease: A Cohort Study With 3.4 Years of Follow-Up

Background Restless legs syndrome (RLS) is associated with higher cardiovascular disease (CVD) risk. However, it remains unknown whether treatment of RLS lowers the cardiovascular risk associated with RLS. Methods and Results All data were collected retrospectively, but subjects were prospectively followed forward in time to determine outcomes of interest. We used the Truven Health MarketScan Commercial Claims and Encounters database from January 1, 2006, through December 31, 2014. Participants were 169 393 individuals, which included 24 199 nonpregnant participants with an RLS diagnosis (16 694 receiving treatments for RLS and 7505 without treatment) during 2006 to 2008 and 145 194 age- and sex-matched participants without RLS. All participants were free of CVD before January 1, 2009 (analysis baseline). Incident CVD cases (myocardial infarction, angina, stroke, atrial fibrillation, and heart failure) were identified. We adjusted for potential confounders, such as presence of chronic conditions and medication use. We identified 16 574 incident CVD cases during 2009 to 2014. Relative to the non-RLS group, the adjusted hazard ratio (HR) for future CVD was 1.26 (95% CI, 1.20-1.32) (P<0.001) for the RLS with treatment group, and 1.53 (95% CI, 1.42-1.65) (P<0.001) for the RLS without treatment group. Significant lower CVD risk was observed for all different RLS treatments, including dopaminergics, anticonvulsants, benzodiazepines, and opiates (adjusted HRs range, 0.71-0.84; P<0.001 for all), except for ergot-dopamine use. Conclusions RLS was associated with higher future CVD risk. However, RLS was associated with statistically significantly less future cardiovascular risk in RLS patients with treatment than in those without treatment.

Effectiveness and safety of massage in the treatment of restless legs syndrome: A protocol for systematic review and meta analysis

BACKGROUND

Restless legs syndrome (RLS), known as a kind of neurological disease, is prevalent but easy to be ignored. Studies have demonstrated that massage therapy can effectively reduce the symptoms of patients with RLS and improve their quality of life. However, the efficacy of massage therapy for RLS is still controversial. Therefore, this protocol aims to evaluate the reliability of massage therapy in treating RLS in a thorough way.

METHODS

We will search relevant randomized controlled trials from Chinese Biomedical Literature Database, Chongqing VIP, CNKI, Wanfang, Web of Science, Cochrane Library, PubMed, and EMBASE, when publication status and language are not considered and the time limit ends with September 6, 2020. Two experienced researchers will use RevMan V.5.3 software to perform the selection of literature, data collection, data analysis and synthesis separately. Besides, the quality of trials involved in this study will be measured with the Cochrane bias risk assessment tool.

RESULTS

This protocol will be applied to carry out a systematic evaluation of the massage therapy purposed to treat RLS for its effectiveness and safety.

CONCLUSION

The review will provide a credible evidence suggesting whether massage therapy is a reliable intervention for RLS.

INPLASY REGISTRATION NUMBER

INPLASY202090038.

Survival in Restless Legs Syndrome: An 11-Year Surveillance, Community-Based Population Study

<b><i>Background:</i></b> A growing body of evidence relates restless legs syndrome (RLS) to an increased risk of mortality attributable to both cerebrovascular and cardiovascular events. The aim was to investigate survival in patients with RLS. <b><i>Methods:</i></b> This was an observational, retrospective longitudinal study of a cohort of patients followed up for 11 years. RLS was diagnosed by a physician using the International RLS Study Group criteria. Mortality was analyzed using age-standardized mortality ratios (SMR: observed/expected deaths) and Cox regression analysis. <b><i>Results:</i></b> Vital status was studied in a cohort of 232 patients: 181 women (78%), 96 with RLS (41.4%) with a mean age at baseline of 49.8 ± 15.0 years and a mean RLS duration of 14.1 ± 1.9 years, and 136 non-RLS (58.6%) with a mean age of 51.3 ± 14.9 years. This RLS cohort was followed up for a period of 10.4 ± 2.0 years. As of September 2019, 17 (7.3%) patients died (6 with RLS, 6.3%), and the most frequent cause was oncological (66.7%). A total of 944 person-years of observations were available for survival analysis. RLS was not associated with increased mortality in adjusted Cox regression analysis (HR = 1.12, 95% CI: 0.40–3.15), and survival was similar to that expected for the general population (SMR = 0.61, 95% CI: 0.27–1.36). <b><i>Conclusions:</i></b> RLS seems not to be associated with increased mortality compared to the general population. Still, studies with prospective data collection with large samples are needed to study the long-term mortality risk factors in RLS cohorts.

The Goals of Treating Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) syndrome is a destructive and insidious entity mostly underdiagnosed and undertreated. It affects not only individuals but the society as a whole. The costs to the populations can be measured not only in morbidity and mortality but also in the financial wellbeing of a society. Financial burden of this disease is staggering. The social fabric of society is also greatly impacted. Physiologic effects of OSA are far reaching. It has been shown that early intervention with treatment of OSA can often prevent and/or reverse many of the negative outcomes associated with this condition.

Sleep patterns, genetic susceptibility, and incident cardiovascular disease: a prospective study of 385 292 UK biobank participants

AIMS

To quantify the association of combined sleep behaviours and genetic susceptibility with the incidence of cardiovascular disease (CVD).

METHODS AND RESULTS

This study included 385 292 participants initially free of CVD from UK Biobank. We newly created a healthy sleep score according to five sleep factors and defined the low-risk groups as follows: early chronotype, sleep 7-8 h per day, never/rarely insomnia, no snoring, and no frequent excessive daytime sleepiness. Weighted genetic risk scores of coronary heart disease (CHD) or stroke were calculated. During a median of 8.5 years of follow-up, we documented 7280 incident CVD cases including 4667 CHD and 2650 stroke cases. Compared to those with a sleep score of 0-1, participants with a score of 5 had a 35% (19-48%), 34% (22-44%), and 34% (25-42%) reduced risk of CVD, CHD, and stroke, respectively. Nearly 10% of cardiovascular events in this cohort could be attributed to poor sleep pattern. Participants with poor sleep pattern and high genetic risk showed the highest risk of CHD and stroke.

CONCLUSION

In this large prospective study, a healthy sleep pattern was associated with reduced risks of CVD, CHD, and stroke among participants with low, intermediate, or high genetic risk.

Prevalence and Risk Factors of Restless Legs Syndrome in Hemodialysis Patients

OBJECTIVE

The current study aimed to investigate the prevalence and risk factors of restless legs syndrome (RLS) in patients undergoing hemodialysis, as well as the mortality and risks of cardiovascular and cerebrovascular events.

METHODS

A total of 354 hemodialysis patients from four hospitals were enrolled. RLS was diagnosed using the International RLS Study Group (IRLSSG) criteria. The patients were evaluated face-to-face using the IRLSSG rating scale, Epworth Sleepiness Scale (ESS), Hamilton Anxiety Scale, Hamilton Depression Scale, and Pittsburgh Sleep Quality Index (PSQI). The patients were followed up for 9 months. Death was considered an endpoint event. The cardiovascular and cerebrovascular events were investigated.

RESULTS

The prevalence of RLS in hemodialysis patients was 40.7% and was associated with factors such as duration of hemodialysis, hypersensitive C-reactive protein, hyperparathyroidism, glycosylated serum protein, and erythropoietin treatment. The scores of the PSQI, ESS, and Hamilton Depression Scale in the RLS group were significantly higher than those in the non-RLS group (p < 0.05). During follow-ups, the incidence rate of cardiovascular diseases was 18.8% in the RLS group and 8.6% in the non-RLS group (p < 0.005). The IRLSSG rating scores were significantly higher in RLS patients with kidney transplantation failure compared with those without transplantation (p < 0.05).

CONCLUSION

The prevalence of RLS was high in hemodialysis patients. The risk factors of RLS included duration of hemodialysis, hypersensitive C-reactive protein, hyperparathyroidism, glycosylated serum protein, and erythropoietin treatment. RLS affected sleep quality and emotion and increased the risk of cardiovascular diseases in hemodialysis patients. RLS was more severe in patients with kidney transplantation failure compared with those without transplantation.

Association of Restless Legs Syndrome With Risk of Suicide and Self-harm

IMPORTANCE

Restless legs syndrome (RLS) is a common neurologic disorder that has been previously found to be associated with higher odds of suicidal ideation. In the context of the increasing suicide rate in the United States, the evidence regarding the association between RLS and the risk of suicide and self-harm is limited.

OBJECTIVE

To investigate the association between RLS and risk of suicide and self-harm.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was performed using Truven Health MarketScan national claims data from 2006 to 2014; the baseline data were from 2006 to 2008, and the follow-up data covered 6 years (January 1, 2009, to December 31, 2014). Included were 24 179 nonpregnant participants with RLS and 145 194 age- and sex-matched participants without RLS at baseline (2006-2008), who were free of suicide, self-harm, cardiovascular disease, or cancer at study baseline. Data analysis was performed from February 1, 2018, to January 1, 2019.

EXPOSURE

Diagnosis of RLS, as identified by the International Classification of Diseases, Ninth Revision code.

MAIN OUTCOMES AND MEASURES

Incident suicide and self-harm event, identified by the International Classification of Diseases, Ninth Revision diagnosis code.

RESULTS

Among 169 373 participants in the current analysis, the mean (SD) age was 49.4 (9.1) years; 53 426 (31.5%) participants were men. During a mean (SD) follow-up duration of 5.2 (2.2) years, 119 incident suicide and self-harm cases were identified. Individuals with RLS had a higher risk of suicide or self-harm compared with those without RLS (adjusted hazard ratio, 2.66; 95% CI, 1.70-4.15), after adjusting for lifestyle factors (eg, alcohol and obesity), presence of chronic diseases (eg, depression, insomnia, diabetes, chronic kidney disease, peripheral neuropathy, iron-deficiency anemia, and Parkinson disease), and use of medications. Excluding those with depression, insomnia, obstructive sleep apnea, and other common chronic conditions, the significant association between RLS and suicide or self-harm persisted (adjusted hazard ratio, 4.14; 95% CI, 2.17-7.92).

CONCLUSIONS AND RELEVANCE

Restless legs syndrome was associated with a high risk of suicide and self-harm, and the risk was independent of most identified diseases and conditions.

Is Restless Legs Syndrome Associated with an Increased Risk of Mortality? A Meta-Analysis of Cohort Studies

Background

Restless legs syndrome (RLS) is a common sleep disorder,. although controversial, growing evidence relates the presence of RLS to an increased risk of mortality, mainly due to cardiovascular events. The aim of this article was to review the role of RLS as a risk factor of mortality according to independent cohort studies.

Methods

We performed a literature review via PubMed database for articles relating RLS and mortality. We used the random-effects model to calculate the pooled effect estimates on mortality. Heterogeneity between studies was assessed using quantitative and qualitative analysis.

Results

Out of 100 articles identified, 13 were finally included. Although studies were heterogeneous (p = 0.001), no significant publication bias was found. When all cohort studies were considered, the random-effects model yielded a significantly increased risk of mortality in RLS versus non-RLS patients (13 studies, hazard ratio [HR] = 1.52, 95% confidence interval [CI] 1.28-1.80). However, this association was not statistically significant when only cohort studies using the international RLS diagnostic criteria were considered (5 studies, HR = 1.63, 95% CI 0.94-2.81).

Discussion

The results of this meta-analysis suggest that RLS seems to be a risk factor of mortality, although this association is conditioned by the diagnostic criteria used in the studies. Future long-term follow-up standardized mortality studies are needed to address this important question that carries potential impact on population global health.

Restless legs syndrome, periodic limb movements during sleep and cardiovascular risk

Multiple mechanisms may modulate an association between restless legs syndrome/Willis-Ekbom disease (RLS/WED) and cardiovascular disease (CVD), including chronic sleep deprivation, intermittent, periodic limb movements in sleep (PLMS)-related autonomic fluctuations and possible autonomic dysfunction intrinsically associated with RLS per se. The purpose of this paper is to review the existing RLS/WED literature focusing on the pathophysiologic evidence for possible associations between RLS/WED and PLMS with CVD and events (CVE). Specific intrinsic dysautonomic aspects of the disease, which may contribute to generating CVD, are separately discussed. The association between RLS/WED and both CV risk factors and CVD still remains elusive. Although several shared pathophysiological causes could explain these possible relationships, the emerging body of literature focusing on these disorders remains controversial. Not only longitudinal population-based studies and meta-analyses, but also more animal models and therapeutic interventions are needed in order to build a sufficiently robust body of evidence on this topic.

Prevalence and Significance of Restless Legs Syndrome in Patients With Coronary Artery Disease

Restless legs syndrome (RLS), characterized by leg restlessness and dysesthesia predominantly at night and at rest, disrupts sleep and quality of life. The reported prevalence of RLS is 2% to 5%. Although a relation between RLS and coronary artery disease has been suggested, the prevalence and clinical significance of RLS in coronary artery disease patients remain unknown. We enrolled coronary artery disease patients who underwent percutaneous coronary intervention. Patients with RLS were identified according to international criteria. Subjective sleepiness, sleep quality, and health-related quality of life were assessed using the Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, and Short Form-8, respectively. Among 326 patients with coronary artery disease, 26 (8.0%) had RLS. There were no significant differences in characteristics between patients with and without RLS. Sleep quality and quality of life were more disrupted in patients with RLS (Pittsburgh Sleep Quality Index score, 7.4 ± 2.4 vs 5.6 ± 2.5, p <0.001; physical component summary and mental component summary scores of Short Form-8, 39.6 ± 1.8 vs 43.5 ± 0.5, p = 0.042 and 45.2 ± 8.4 vs 48.4 ± 7.4, p = 0.037, respectively), despite no significant difference in Epworth Sleepiness Scale score (8.2 ± 5.1 vs 7.1 ± 4.8, p = 0.293). In multiple linear regression analyses, RLS was independently associated with Pittsburgh Sleep Quality Index (β = 0.174, p <0.001), physical component summary (β = -0.127, p = 0.029), and mental component summary (β = -0.113, p = 0.042) scores. In conclusion, in patients with coronary artery disease, the prevalence of RLS was relatively high compared to that reported in the general population. The presence of RLS was associated with disrupted sleep quality and health-related quality of life in coronary artery disease patients.

Acute-onset Restless legs syndrome in acute neurological conditions-a prospective study on patients with the Guillain-Barre syndrome and acute stroke

OBJECTIVES

While the Restless legs syndrome (RLS) is usually recognized as a chronic condition, it has often been diagnosed among patients with acute neurological illnesses, in which limb discomfort is reported. This study was conducted to determine how many among these, actually have acute-onset RLS, and also to evaluate characteristics of this subgroup of patients with Guillain-Barre syndrome (GBS) and stroke developing acute-onset RLS.

METHODS

Consecutive patients diagnosed with GBS and eligible stroke patients, admitted to our Neurology services over a 1-year period, were enrolled. They were evaluated for symptoms of RLS based on IRLSSG consensus criteria and the AIIMS RLS Questionnaire for Indian patients (ARQIP).

RESULTS

Forty adults with GBS and 58 with stroke were included. A total of 10 of the 40 (25%) patients with GBS developed definite acute RLS, which was mostly monophasic. Seven (70%) of these had demyelinating type of GBS, a significant association with acute RLS (P = .024). Six of the 58 stroke patients (10%) developed definite acute-onset, often persistent RLS. Subcortical location showed significant association with increased risk of developing acute RLS (P < .001). All patients diagnosed with acute-onset RLS had an immediate and good response to dopamine agonists.

CONCLUSION

This is the first study showing that acute-onset RLS is common, affecting nearly 25% of patients with GBS and 10% patients with acute stroke. Recognizing and treating it can majorly contribute toward symptom relief and early improvement in the quality of life for this population.

Risk of dementia in patients with primary insomnia: a nationwide population-based case-control study

BACKGROUND

To investigate the association between primary insomnia and dementia using a Taiwanese population-based database.

METHODS

This case-control study involved a subset of Taiwan's National Health Insurance Research Database of reimbursement claims. We included 51,734 patients who were diagnosed with primary insomnia from 2002 to 2004 as the test group and 258,715 nonprimary insomnia participants aged 20 years or older as the reference group. We excluded patients under 20 and those with depression, post-traumatic stress disorder, and/or sleep disorders caused by organic lesion(s), drugs, or alcohol. We used a Cox proportional hazards model to assess the primary insomnia on the risk of developing dementia after adjusting for sociodemographic characteristics and comorbidities.

RESULTS

The primary insomnia cohort had a higher prevalence of diabetes, dyslipidemia, hypertension, coronary heart disease, chronic liver disease, and chronic kidney disease at baseline. After adjusting for select comorbidities, primary insomnia remained a significant predisposing factor for developing dementia, and was associated with a 2.14-fold (95% confidence interval, 2.01-2.29) increase in dementia risk. We also found a higher risk of dementia in younger patients.

CONCLUSIONS

Taiwanese patients with primary insomnia, especially those under 40, had a higher risk of developing dementia than those without primary insomnia.

Sleep Disturbances as a Risk Factor for Stroke

Sleep, a vital process of human being, is carefully orchestrated by the brain and consists of cyclic transitions between rapid eye movement (REM) and non-REM (NREM) sleep. Autonomic tranquility during NREM sleep is characterized by vagal dominance and stable breathing, providing an opportunity for the cardiovascular-neural axis to restore homeostasis, in response to use, distress or fatigue inflicted during wakefulness. Abrupt irregular swings in sympathovagal balance during REM sleep act as phasic loads on the resting cardiovascular system. Any causes of sleep curtailment or fragmentation such as sleep restriction, sleep apnea, insomnia, periodic limb movements during sleep, and shift work, not only impair cardiovascular restoration but also impose a stress on the cardiovascular system. Sleep disturbances have been reported to play a role in the development of stroke and other cardiovascular disorders. This review aims to provide updated information on the role of abnormal sleep in the development of stroke, to discuss the implications of recent research findings, and to help both stroke clinicians and researchers understand the importance of identification and management of sleep pathology for stroke prevention and care.

Restless legs syndrome and cerebrovascular/cardiovascular events: Systematic review and meta-analysis

OBJECTIVE

We performed a systematic review and meta-analysis to evaluate the proposed association of restless legs syndrome (RLS) with cerebrovascular/cardiovascular outcomes.

METHODS

We calculated the corresponding odds ratios on the prevalence of cerebrovascular/cardiovascular risk factors and standardized mean differences on the reported mean age at baseline between RLS patients and controls. We also calculated the corresponding risk ratios and adjusted for potential confounders hazard ratios (HRs_adjusted ) on the reported outcomes of interest between RLS patients and controls.

RESULTS

We identified 8 eligible studies (644 506 patients, mean age: 60.2 years, 36.2% males; 3.3% with RLS). RLS patients were found to have significantly higher prevalence of hypertension (P = .002), diabetes (P = .003) and hyperlipidemia (P = .010) compared to controls. In the unadjusted analyses of prospective observational studies, RLS patients were found to have significantly higher risk for cerebrovascular ischaemia (P = .01) and all-cause mortality (P = .04) compared to controls during follow-up, while in the adjusted for potential confounders analyses RLS patients were only found to have a higher risk of all-cause mortality (HR adjusted=1.52, 95% CI: 1.17-1.97, P = .002).

CONCLUSIONS

The present report does not provide evidence for an increased risk of cerebrovascular and cardiovascular events in RLS patients, which highlights the vast presence of confounding factors.

Prospective study of restless legs syndrome and total and cardiovascular mortality among women

OBJECTIVE

We prospectively examined whether women with physician-diagnosed restless legs syndrome (RLS) had a higher risk of total and cardiovascular disease (CVD) mortality relative to those without RLS.

METHODS

The current study included 57,417 women (mean age 67 years) from the Nurses' Health Study without cancer, renal failure, and CVD at baseline (2002). Main outcomes were total and CVD mortality. We used the Cox proportional hazards model to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and CVD-specific mortality based on RLS status, adjusting for age, presence of major chronic diseases, and other potential confounders.

RESULTS

We documented 6,448 deaths during 10 years of follow-up. We did not observe a significant association between presence of physician-diagnosed RLS and high risk of total mortality (adjusted HR 1.15, 95% CI 0.98-1.34). When cause-specific mortality was studied, participants with RLS had a significantly higher risk of CVD mortality (adjusted HR 1.43, 95% CI 1.02-2.00) relative to those without RLS after adjustment for potential confounders. Longer duration of RLS diagnosis was significantly associated with a higher risk of CVD mortality (p for trend = 0.04). Excluding participants with common RLS comorbidities strengthened the association between RLS and total (adjusted HR 1.43, 95% CI 1.03-1.97) and CVD mortality (adjusted HR 2.27, 95% CI 1.21-4.28). However, we did not find a significant association between RLS and mortality due to cancer and other causes.

CONCLUSIONS

Women with RLS had a higher CVD mortality rate, which may not be fully explained by common co-occurring disorders of RLS.

Association of Restless Legs Syndrome With Incident Parkinson's Disease

Study Objectives

The association between restless legs syndrome (RLS) and Parkinson's disease (PD) has been extensively studied with inconclusive results; therefore, we prospectively examined the associations of the presence of RLS with development of incident PD.

Methods

From a nationally representative prospective cohort of almost 3.5 million US veterans (age: 60 ± 14 years, 93% male, median follow-up time of 7.8 years [interquartile range: 6.4-8.4 years]), we created a propensity-matched cohort of 100882 PD-free patients and examined the association between prevalent RLS and incident PD. This association was also assessed in the entire cohort. Associations were examined using Cox models.

Results

There were 68 incident PD events (0.13%, incidence rate 1.87 [1.48-2.37]/10000 patient-years) in the RLS-negative group, and 185 incident PD events (0.37%, incidence rate 4.72 [4.09-5.45]/10000 patient-years) in the RLS-positive group in the propensity-matched cohort. Prevalent RLS was associated with more than twofold higher risk of incident PD (hazard ratio [HR]: 2.57, 95% confidence interval [CI]: 1.95-3.39) compared to RLS-negative patients. Qualitatively similar results were found when we examined the entire 3.5 million cohort: Prevalent RLS was associated with more than twofold higher risk of incident PD (multivariable adjusted HR: 2.81, 95%CI: 2.41-3.27).

Conclusion

RLS and PD share common risk factors. In this large cohort of US veterans, we found that prevalent RLS is associated with higher risk of incident PD during 8 years of follow-up, suggesting that RLS could be an early clinical feature of incident PD.

Survival of Dialysis Patients with Restless Legs Syndrome: A 15-Year Follow-Up Study

BACKGROUND

Restless legs syndrome, also known as Willis/Ekbom disease (RLS/WED), is a sleep-related, sensorimotor disorder with a high prevalence among end-stage renal disease (ESRD) patients undergoing haemodialysis (HD) (about 15-40%). Whether RLS/WED in uremic patients influences cardiovascular morbidity and mortality remains a matter of controversy. The aim of this study was to evaluate the relationship of RLS/WED and mortality in a population of chronically dialyzed patients.

METHOD

In 1996, we studied 128 patients with ESRD undergoing HD; 47 subjects (36.7%) complained RLS/WED symptoms. Fifteen years later we evaluated the mortality of this population. No clinical follow-up examination of the uremic population was made. The Kaplan-Maier curves in dialysis patients with or without RLS/WED (control group matched for age) were constructed for all-cause mortality and compared using log-rank test.

RESULTS

The Kaplan-Maier curves disclosed a lower mortality rate in the uremic patients with RLS/WED than in those without RLS/WED (p = 0.04). In our analysis, the mortality rate was not influenced by RLS/WED severity (p = 0.11) or gender (p = 0.15). No difference among the causes of death was found in the 2 groups.

CONCLUSIONS

Our study suggests that mortality in ESRD patients is not influenced by concomitant RLS/WED. After a 15-year follow-up, survival rates in our cohort were significantly longer in uremic subjects with RLS/WED than in those without RLS/WED. Finally, we found no relationship between RLS/WED severity and mortality.

Association of Sleep Duration, Symptoms, and Disorders with Mortality in Adults with Chronic Kidney Disease

INTRODUCTION

In general populations, short and long sleep duration, poor sleep quality and sleep disorders have been associated with increased risk of death. We evaluated these associations in individuals with chronic kidney disease (CKD).

METHODS

Prospective cohort study of 1,452 National Health and Nutrition Examination Survey (NHANES) 2005-2008 participants with CKD. CKD was defined by estimated glomerular filtration rate <60 ml/min/1.73m² or urine albumin-to-creatinine ratio ≥30 mg/g. Sleep duration, sleep symptoms (difficulty falling asleep, difficulty staying asleep, daytime sleepiness and non-restorative sleep), and sleep disorders (restless legs syndrome and sleep apnea) were self-reported. Vital status was determined using NHANES mortality linkage through December 2011.

RESULTS

Mean age was 61 years, 58% were women, and 75% non-Hispanic white. During 4.4 years of median follow-up, we observed 234 deaths of which 75 were due to cardiovascular causes. In multivariable analyses, compared with individuals who reported 7-8 hours of sleep, HR (95% CI) for all-cause mortality for sleep duration <7 hours and >8 hours were 1.50 (1.08-2.10) and 1.36 (0.89-2.08), respectively. The corresponding HR (95%CI) for cardiovascular mortality were 1.56 (0.72-3.37) and 1.56 (0.66-3.65). Non-restorative sleep and restless legs syndrome were associated with increased risk for all-cause mortality (1.63 [1.13-2.35], and 1.69 [1.04-275], respectively).

CONCLUSION

In adults with CKD, short sleep duration, nonrestorative sleep and restless legs syndrome are associated with increased risk of death. These findings underscore the importance of promoting adequate sleep in patients with CKD, and the need for future studies evaluating the impact of sleep interventions in this population.

Associations of Incident Cardiovascular Events With Restless Legs Syndrome and Periodic Leg Movements of Sleep in Older Men, for the Outcomes of Sleep Disorders in Older Men Study (MrOS Sleep Study)

Study Objectives

Both restless legs syndrome (RLS) and periodic leg movements in sleep (PLMS) may be associated with incident cardiovascular disease (CVD). However, the individual contributions of these factors to adverse CVD outcomes are unknown.

Methods

During the MrOS Sleep Study, 2823 men (mean age = 76.3 years) participated in a comprehensive sleep assessment from 2000 to 2002. RLS was identified by self-report of a physician diagnosis of RLS. A periodic limb movement of sleep index (PLMI) was derived from unattended in-home polysomnography. Incident cardiovascular events were centrally adjudicated during 8.7 ± 2.6 years of follow-up. The primary outcome was all-cause CVD; secondary outcomes included incident myocardial infarction (MI) and cerebrovascular disease. Cox proportional hazards regression models were adjusted for multiple covariates, including PLMI, to examine if there were independent associations of RLS and PLMI to the outcomes.

Results

Physician-diagnosed RLS was reported by 2.2% and a PLMI ≥ 15 was found in 59.6% of men. RLS was not associated with the composite CVD outcome. RLS was significantly associated with incident MI (Hazard ratio [HR] = 2.02, 95% CI, 1.04-3.91) even after adjustment for multiple covariates. Results were only modestly attenuated when PLMI was added to the model. PLMI also was found to predict incident MI (per SD increase in PLMI, HR = 1.14, 95% CI, 1.00-1.30, p = .05), and was materially unchanged after addition of RLS.

Conclusions

The independent risk that RLS confers for MI suggests a role for non-PLMS factors such as sleep disturbance, shared genetic factors, or PLM-independent sympathetic hyperactivity.

Prognostic value of restless legs syndrome in hemodialysis patients: a systematic review and meta-analysis

BACKGROUND

Previous studies have revealed that restless legs syndrome (RLS) not only is frequently prevalent in dialysis patients but also increases the risk of death in dialysis patients, especially in hemodialysis (HD) patients. However, inconsistent results also still exist, having attracted confusion and discussion. Owing to mixed and inconclusive results, we conducted to perform the comprehensive meta-analysis to evaluate the potential prognostic value of RLS in HD patients.

MATERIALS AND METHODS

We conducted a systematic literature search using electronic databases (PubMed, Ovid, Embase and Web of Science) to identify relevant studies reporting on all-cause mortality and cardiovascular (CV) events in HD patients suffering from RLS. We searched the literature published up to December 5, 2016, or earlier. We used both fixed- and random-effects models to calculate the overall effect estimate. An I²>50% indicates at least moderate statistical heterogeneity. A sensitivity analysis and subgroup analysis were performed to find the origin of heterogeneity.

RESULTS

A total of four studies including 1,839 patients found that there was no significant association between RLS and all-cause mortality (hazard ratio [HR]: 1.649; 95% confidence interval [CI]: 0.778-3.496) and CV events (HR: 0.863; 95% CI: 0.600-1.127) in HD patients. Heterogeneity among the studies was observed for all-cause mortality (I²=80.7%, P=0.001).

CONCLUSION

Our meta-analysis suggests that there was no significant effect of RLS on all-cause mortality and CV events in HD patients. Therefore, large-scale and well-designed studies are needed to validate the association between RLS and the risk of death in HD patients.

Restless legs syndrome and cardiovascular disease: a research roadmap

In this paper, we first critically appraise the epidemiologic literature examining the association of restless legs syndrome (RLS) with cardiovascular disease (CVD) and then consider whether lessons learned from the study of cardiovascular consequences of other sleep disorders might inform a research agenda to examine the potential mechanisms of cardiovascular morbidity of RLS. Cross-sectional and longitudinal studies are both mixed as to whether there is a meaningful association of RLS and CVD. On the other hand, numerous cross-sectional and longitudinal observational studies have shown a strong association of obstructive sleep apnea (OSA) with CVD risk. Each of the potential mediating mechanisms in OSA may also be assessed in RLS, including 1) neural mechanisms such as increased central sympathetic outflow, impaired baroreflex function, diminished heart rate and blood pressure variability, and increased chemoreflex sensitivity, 2) metabolic mechanisms such as glucose intolerance and reduced insulin sensitivity/diabetes as a result of sleep disturbance in RLS, 3) oxidative stress, 4) systemic or vascular inflammatory mechanisms, and 5) vascular mechanisms including impaired endothelial functioning, increased aortic stiffness, hypothalamic-pituitary axis activation or renin-angiotensin-aldosterone activation. Three known characteristics of RLS may contribute to these specific mechanisms of increased cardiovascular risk: 1) periodic limb movements of sleep, which are associated with large increases in heart rate and blood pressure, 2) sleep fragmentation and sleep deprivation, which are known to produce adverse consequences for neural, metabolic, oxidative, inflammatory, and vascular systems, and 3) iron deficiency, which is an emerging risk for cardiovascular disease. Future research priorities include additional epidemiologic studies which characterize multiple CVD risk factors, case-control studies which examine known markers of cardiovascular risk, and small clinical trials which assess the effects of RLS treatment on intermediate physiological markers such as sympathetic activity or baroreflex control, measures of vascular stiffness and reactivity, or measures of insulin sensitivity and glucose tolerance.

Role of sleep-disordered breathing and sleep-wake disturbances for stroke and stroke recovery

Background:

Sleep-disordered breathing (SDB) and sleep-wake disturbances (SWD) are highly prevalent in stroke patients. Recent studies suggest that they represent both a risk factor and a consequence of stroke and affect stroke recovery, outcome, and recurrence.

Methods:

Review of literature.

Results:

Several studies have proven SDB to represent an independent risk factor for stroke. Sleep studies in TIA and stroke patients are recommended in view of the very high prevalence (>50%) of SDB (Class IIb, level of evidence B). Treatment of obstructive SDB with continuous positive airway pressure is recommended given the strength of the increasing evidence in support of a positive effect on outcome (Class IIb, level of evidence B). Oxygen, biphasic positive airway pressure, and adaptive servoventilation may be considered in patients with central SDB. Recently, both reduced and increased sleep duration, as well as hypersomnia, insomnia, and restless legs syndrome (RLS), were also suggested to increase stroke risk. Mainly experimental studies found that SWD may in addition impair neuroplasticity processes and functional stroke recovery. Treatment of SWD with hypnotics and sedative antidepressants (insomnia), activating antidepressants or stimulants (hypersomnia), dopaminergic drugs (RLS), and clonazepam (parasomnias) are based on single case observations and should be used with caution.

Conclusions:

SDB and SWD increase the risk of stroke in the general population and affect short- and long-term stroke recovery and outcome. Current knowledge supports the systematic implementation of clinical procedures for the diagnosis and treatment of poststroke SDB and SWD on stroke units.