A case-control study on restless legs syndrome in nondialyzed patients with chronic renal failure

Association between Chronic kidney disease and restless leg syndrome (RLS): a systematic review and meta-analysis

Restless leg syndrome (RLS) is characterized by unpleasant nocturnal sensations in the lower limbs, and it has emerged as the fourth leading cause of insomnia and is often an underdiagnosed medical condition among sleep disorders. The symptoms of RLS are more common in chronic kidney disease patients than in the general population. Therefore, we performed the first meta-analysis to estimate the risk of RLS among chronic kidney disease patients. We conducted a comprehensive search in Embase, Ovid-MEDLINE, PubMed, Scopus, Web of Science, and CINAHL databases. Data were analyzed with the random-effects model using Comprehensive Meta-Analysis (CMA) software to find the odds ratio (OR). The heterogeneity was checked with the I2 test and Cochran's Q-statistic, and we performed the moderator analysis to find potential sources of heterogeneity. The study quality was assessed using the Newcastle-Ottawa Scale. Of 1175 studies, we found nine studies, with a total of 18,983 participants. The pooled OR of RLS among chronic kidney disease was 5.64 (95%CI 2.70-11.78). Regarding moderator analysis results, it was observed that higher body mass index and abnormal laboratory results would increase the risk of RLS; however, the statistical test was not significant in the current study. The findings reveal a substantial sixfold increase in the likelihood of RLS when compared to the general population. Therefore, health professionals should encourage patients to adhere to the treatment and practice a healthy lifestyle to manage their condition and reduce the risk of RLS. Moreover, future research can develop an intervention to reduce RLS symptoms.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41105-024-00513-4.

A comprehensive update on the ADMET considerations for α2δ calcium channel ligand medications for treating restless legs syndrome

INTRODUCTION

Restless legs syndrome/Willis-Ekbom disease (RLS/WED) is a sleep-related sensory-motor disorder associated with poor sleep quality and impaired daily functioning. In patients affected by chronic RLS/WED, a pharmacological therapy is recommended. International guidelines suggest to start the treatment with a α2δ calcium channel ligand in most cases, unless contraindicated.

AREAS COVERED

The present review is based on an extensive Internet and PubMed search from 1986 to 2024. Our purpose is to describe the absorption, distribution, metabolism, and toxicology (ADMET) of the α2δ ligands, with common consideration for the therapeutic class, specificities of different compounds, efficacy, and safety in relation to other treatment options.

EXPERT OPINION

α2δ ligands are quite similar in their ADMET profiles, sharing most of the pharmacokinetics and potential adverse effects. However, we highlight the linear kinetic of gabapentin enacarbil and pregabalin, differently from gabapentin. α2δ ligands are safe and effective for the treatment of RLS/WED. Additional benefits can be obtained in comorbid insomnia, chronic pain syndromes, history of impulse control disorder, and comorbid anxiety. The use of α2δ ligands is associated with poor risk of augmentation. We still need new long-term safe and effective treatments, which could be developed along with our knowledge of RLS/WED pathophysiology.

Restless leg syndrome in patients with chronic kidney disease: a hospital-based study from Upper Egypt

OBJECTIVES

Chronic kidney disease (CKD) is a common cause of restless leg syndrome (RLS). RLS is under-recognized, misdiagnosed and undertreated disorder in our locality. In this study, we aimed to determine the prevalence of RLS due to CKD and its predictors.

METHODS

This cross-sectional study included 520 patients [male = 200; female = 320; age: 48.45 ± 3.63yrs; uremia duration: 6.44 ± 1.65yrs; CKD5D = 400; CKD3D = 120). RLS diagnosis was done by clinical interviewing according to International RLS Study Group criteria. All underwent detailed biochemical testing and iron and ferritin levels' measurements. Insomnia, depression and anxiety severities were assessed using insomnia sleep index (ISI), Beck Depression Inventory (BDI-II) and State-Trait Anxiety Inventory for Adults (STAI-AD) scales.

RESULTS

RLS was found in 22.31% [ESKD = 26%, CKD3D = 10%]. Insomnia, depression and anxiety were found in 76.15%, 91.15% and 44.23%, respectively. Insomnia was correlated with depression (r = 0.488, p = 0.001) and anxiety (r = 0.360, p = 0.006) but not RLS. Multiple linear regression analysis showed that ESKD (OR = 3.8, 95%CI = 2.5-8.5, p = 0.001), inadequate dialysis (OR = 4.6, 95%CI = 3.5-8.6, p = 0.001), hyperparathyroidism (OR = 5.1, 95%CI 3.2-13.7, p = 0.0001) and peripheral neuropathy (OR = 5.6, 95%CI = 3.8-12.8, p = 0.0001) were independently associated with RLS.

CONCLUSION

The prevalence of RLS with CKD is 22.31%. It is 2.6 times more frequent and severe with ESKD compared to CKD3D. It seems that RLS may occur early with CKD and becomes worse with progressive kidney impairment. Also, insomnia, depression and anxiety are common with CKD, however, their severities were not correlated with RLS. Predictors for RLS were ESKD, inadequacy of dialysis, hyperparathyroidism and peripheral neuropathy.

Correlation between vitamin D and poor sleep status in restless legs syndrome

BACKGROUND

Restless Legs Syndrome (RLS) is closely related to poorer sleep quality. Vitamin D can regulate sleep regulation, cell proliferation, and differentiation. To measure whether vitamin D has predictive value for poor sleep quality in RLS was our aim in this study.

METHODS

To analyze the serum levels of 25-hydroxyvitamin D [25(OH)D] in 95 RLS patients. We used the Pittsburgh Sleep Quality Index (PSQI) to measure sleep quality. Subjects had been divided into a normal and poor-sleeper groups according to the PSQI score. Using correlation and regression analysis to explore underlying etiologies that affect sleep disorder in RLS patients.

RESULTS

Patients in the poor-sleeper group had significantly lower vitamin D levels in comparison to the normal group. The serum vitamin D levels were negative correlate with PSQI scores after adjusting for confounding factors. In addition, regression analysis showed that vitamin D could act as a predictor for sleep disorders in RLS patients (odds ratio [OR] = 0.008, p = 0.004). The area under the curve (AUC), cut-off value, sensitivity, and specificity of serum vitamin D was 0.967 (95% CI 0.935-0.998), 16.84 ng/ml, 87.5%, and 93.7% by receiver operating characteristic (ROC) analysis.

CONCLUSION

Our study confirmed the relationship between poorer sleep quality and vitamin D in RLS. However, the causal relationship between vitamin D deficiency and RLS is currently inconclusive. The effect of vitamin D supplementation is needed to confirm as the therapeutic strategies for sleep disorders in RLS patients in future work.

The complexity of sleep disorders in dialysis patients

Background

Dialysis patients experience a high burden of physical and emotional symptoms directly affecting their sleep and quality of life. In this study, objective and subjective measurements to quantify sleep were performed, compared with those of healthy controls, and associated with burden of comorbidity and uraemic toxicity.

Methods

A total of 64 dialysis patients were included—10 peritoneal dialysis, 42 in-centre daytime haemodialysis (HD) and 12 in-centre nocturnal HD patients—as well as one-to-one age- and gender-matched healthy controls. Assumed and actual sleep time, sleep efficiency and fragmentation index were measured by actigraphy for at least two consecutive nights. Patients and controls also completed Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI) questionnaires. The patients’ blood was sampled to determine concentrations of a representative series of uraemic toxins and the Davies–Stoke comorbidity index was derived from medical records.

Results

Apart from the assumed sleep time, all objectively and subjectively measured sleep parameters were worse in the dialysis group compared with the healthy controls. No differences were seen in any of the measured sleep parameters among the different dialysis groups. None of the objectively measured sleep parameters were associated with ISI or PSQI scores in dialysis patients, while sleep times were related to the subjective scores in the healthy cohort. Objectively assessed sleep parameters were associated to neither the uraemic toxicity load nor the Davies–Stoke score.

Conclusions

Independent of the modality, dialysis patients have sleep quality much worse than age- and gender-matched healthy controls. The objectively measured sleep parameters could not be associated to the subjective score, uraemic toxicity or comorbidity score, highlighting the need for objective measurements of sleep and clinical guidelines to aid patient management.

Restless Legs Syndrome in Chronic Kidney Disease: Is Iron or Inflammatory Status To Blame?

STUDY OBJECTIVES

Restless legs syndrome (RLS) is increased in pediatric chronic kidney disease (CKD). In adults without CKD, central nervous system iron deficiency is involved in RLS pathogenesis and a low serum ferritin levels is consequently an indication for initiation of iron therapy. However, children with CKD are at risk for iron deficiency and inflammation, which raises serum ferritin. We examined the role of iron deficiency and inflammation in RLS in pediatric CKD.

METHODS

This cross-sectional study examined RLS prevalence in three groups of pediatric patients with CKD: nontransplant, nondialysis CKD (estimated GFR < 60 mL/min/1.73 m²) (n = 27); renal transplant recipients (n = 65); and dialysis (n = 32). RLS was diagnosed using a validated questionnaire. Serum ferritin < 100 ng/mL or transferrin saturation < 20% defined iron deficiency. Serum high sensitivity C-reactive protein ≥ 1 mg/L defined inflammation.

RESULTS

Among 124 patients, RLS prevalence was 15.3%; this did not differ across groups. There was no significant difference in RLS prevalence between those with and without iron deficiency, defined by either reduced ferritin or transferrin. Median ferritin levels in patients with RLS tended to be higher than in those without RLS (51.2 versus 40.1 ng/mL; P = .08). Inflammation (elevated CRP) also did not differ significantly by RLS status (57.9% [with RLS] versus 41.2% [without RLS], P = .18).

CONCLUSIONS

Neither ferritin nor inflammation differentiated pediatric patients with CKD with and without RLS. This study suggests that the factors mediating the pathogenesis and, potentially, treatment, of RLS in pediatric CKD may be different from non-CKD populations.

French consensus: Pharmacoresistant restless legs syndrome

Dopaminergic agonists, α2δ ligands and opioids are, as single-drug therapy, the first line treatment for restless legs syndrome (RLS/Willis-Ekbom disease). However, despite treatment efficacy, exacerbations of RLS may occur with overall worsening in symptoms severity, development of pain and symptoms spreading to other parts of the body, without meeting augmentation syndrome criteria. This development of "drug-resistant" RLS can cause pain, severe insomnia and psychiatric disorders that affect considerably patients' quality of life. The lack of French recommendations for this form of RLS leave physicians with few options to help patients with physical and emotional distress. Our group of neurological experts and sleep specialists proposes a diagnostic and therapeutic strategy to provide better care and appropriate treatment through searching for the organic, psychiatric and/or iatrogenic causes of drug resistance. Once a drug-resistant RLS diagnosis has been confirmed, we recommend an obligatory work-up including: a video-polysomnogram, a biological evaluation including iron status, standard numeration and C-reactive protein level. Treatment will be comorbidity-dependent: dopaminergic agonist would be recommended in case of depression or associated periodic leg movements, α2δ ligand in case of insomnia, complaint of pain, or general anxiety, in association with low-dose opioids if necessary. Strong opioids should be preferred for multiresistant RLS.

Efficacy of Intravenous Iron Sucrose in Hemodialysis Patients with Restless Legs Syndrome (RLS): A Randomized, Placebo-Controlled Study

Background

Restless legs syndrome (RLS) is a common disorder in hemodialysis (HD) patients that causes sleep disturbances and diminished quality of life. Because iron deficiency has been implicated in the pathogenesis of RLS, we sought to investigate the effects of intravenous (IV) iron sucrose on symptoms of RLS in HD patients.

Material/Methods

The study was a randomized, placebo-controlled study of 1000 mg iron sucrose versus normal saline as placebo. Patients were evaluated at baseline and 2 weeks after the last injection. The severity of RLS was assessed using the International RLS Study Group rating scale (IRLS). Blood samples were taken to measure iron parameters reflecting the iron status, including serum ferritin (SF) concentration, percentage transferrin saturation (TSAT%) and hemoglobin (Hb), and other biochemical parameters as safety assessments, including creatinine (Cr), urea, intact parathyroid hormone (iPTH), and the index of urea clearance (Kt/V). Adverse events were monitored in all subjects during the period of infusion.

Results

After 2 weeks, IRLS scores decreased more in the IV-iron group (−7.38±2.03) than in the placebo group (−0.81±2.61) (P=0.000). Serum ferritin, TSAT, and hemoglobin increased more in the IV-iron group (227.63±77.64 μg/L; 26.06±7.77%; 13.98±3.62g/L, respectively) than in the placebo group (SF, p=0.000; TSAT, p=0.000; Hb, p=0.000, respectively). There were no significant differences between IV-iron and placebo groups in Cr, urea, iPTH, and Kt/V. No adverse effects were observed in the study.

Conclusions

IV iron sucrose is a safe and effective treatment for reducing RLS symptoms in HD patients over the short-term.

Effect of Mineral and Bone Metabolism on Restless Legs Syndrome in Hemodialysis Patients

STUDY OBJECTIVES

Restless legs syndrome (RLS) is a highly prevalent sleep disease among patients on hemodialysis. The physiopathology is still unclear, and may be multifactorial. Because of the association between iron metabolism and chronic kidney disease-mineral and bone disorders (CKD-MBD), we hypothesized that both factors would be associated with RLS.

METHODS

We have evaluated hemodialysis patients, in a face-to-face interview for the diagnosis and severity of RLS, as measured by the International Restless Legs Syndrome Study Group. Clinical, demographic, and biochemical characteristics were measured.

RESULTS

Out of 101 adult patients included, RLS was found in 29 (28.7%). Adjusted multinomial regression analysis revealed that age older than 35 years, transferrin saturation less than 47%, serum ferritin level less than 700 ng/mL, hemoglobin level less than 9.8 g/dL, serum phosphate level higher than 5.2 mg/dL, FGF-23 higher than 2,000 RU/mL, and C-reactive protein less than 1.24 mg/dL were independently associated with RLS. RLS was classified as mild, moderate, severe, and very severe in 3.4%, 41.7%, 44.8%, and 10.1% of patients, respectively. Scores of severity correlated significantly with erythropoietin dose/kg/w (p = 0.046), phosphate (p = 0.003), and inversely with serum albumin (p = 0.003) and calcium (p = 0.008). Phosphate and 25(OH)-vitamin D correlated with transferrin saturation. Patients with severe/very severe symptoms were mostly women, presented with lower serum iron, ionic calcium, and serum albumin levels and higher levels of serum phosphate, and higher percentage of 25(OH)-vitamin D deficiency and levels of FGF-23 higher than 2,000 RU/mL than did those with mild/moderate symptoms.

CONCLUSIONS

CKD-MBD factors besides iron metabolism are associated with RLS in patients on hemodialysis, providing new insights into the understanding of RLS in this population.

Prevalence of restless legs syndrome in chronic kidney disease: a systematic review and meta-analysis of observational studies

INTRODUCTION

Nowadays prevalence of restless legs syndrome (RLS) in chronic kidney disease (CKD) patients was reported in many studies, while the results varied. The aim of our study was to investigate the prevalence of RLS in this population, considering different data collecting measures and diagnostic criteria.

METHODS

MEDLINE, Embase, PsycINFO, and Scopus databases were searched for relevant studies. We limited the analyses to studies using clinical interview or questionnaire for diagnosis. Univariate meta-regression analysis was preformed to assess the effects of the disease-related covariates on prevalence estimates. Comprehensive Meta-Analysis 2.0 was used to perform the meta-analysis.

RESULTS

Fifty-one studies were included in the analysis. Prevalence of RLS was varied by renal function and diagnostic methods. Overall prevalence in CKD populations was 24.2% (95%CI, 20.1-28.7). Pooled prevalence of RLS was higher in patients diagnosed by questionnaire than by clinical interview [26.2% (95%CI, 17.9-36.5) vs. 23.6% (95%CI, 19.6-28.1)]. When grouped by CKD setting, the prevalence was 28.4% (95%CI, 24.6-32.6) in dialysis patients, followed by early stages patients [9.9% (95%CI, 5.4-17.5)], and kidney transplant recipients [6.7% (95%CI, 5.6-7.8)].

CONCLUSIONS

Our meta-analysis suggested that more than one-quarter of CKD sufferers, especially those who were on dialysis, were plagued by RLS. Higher sensitivity of diagnostic criteria in interview may be valuable for timely treatment.

Restless Legs Syndrome in Patients With Chronic Kidney Disease

Symptoms of restless legs syndrome (RLS) are common in patients with chronic kidney disease (CKD) on dialysis; symptoms of RLS are estimated to affect up to 25% of patients on dialysis when the international RLS diagnostic criteria are applied. RLS is a neurologic disorder with a circadian rhythmicity characterized by an overwhelming urge to move the legs during rest, which can be relieved temporarily by movement. RLS has been associated with an increase in sleep disturbance, higher cardiovascular morbidity, decreased quality of life, and an increased risk of death in patients with CKD. Although the exact pathophysiology of RLS is unknown, it is thought to involve an imbalance in iron metabolism and dopamine neurotransmission in the brain. The symptoms of moderate to severe RLS can be treated with several pharmacologic agents; however, data specific to patients on dialysis with RLS are lacking. The purpose of this article is to examine the relationship between, and complications of, RLS and CKD both in dialysis and nondialysis patients, and discuss the treatment options for patients on dialysis with RLS.

Management of Restless Legs Syndrome/Willis-Ekbom Disease in Hospitalized and Perioperative Patients

Restless legs syndrome (RLS) is a sensorimotor disorder that can cause significant discomfort, impaired quality of life, poor mood, and disturbed sleep. Because the disorder is chronic and associated with multiple comorbidities, RLS can be seen in an inpatient or perioperative setting. Certain characteristics of the hospitalized or surgical context can exacerbate or unmask RLS. Importantly, RLS and the associated discomfort and insomnia can prolong hospital stay and negatively impact outcomes. RLS medications should be continued during the hospital admission when possible. Avoidance of excessive phlebotomy and medications known to trigger RLS is helpful. Patients should increase activity when acceptable.

Restless legs syndrome in non-dialysis renal patients: is it really that common?

BACKGROUND

Sleep disorders are frequent in chronic kidney disease (CKD). Among them, restless legs syndrome (RLS) may affect up to 60% of patients on dialysis, and it has been related to a poor quality of life and higher cardiovascular risk. Despite its high prevalence in advanced stages of renal disease, RLS frequency in non-dialysis CKD has not been clearly established. The aim of this study was to assess the frequency of RLS in non-dialysis CKD patients (stages 2 to 4) followed in a reference nephrology outpatient clinic.

METHODS

A standardized questionnaire following the international RLS study group diagnostic criteria was self-administered by 110 patients regularly followed in the nephrology clinic. The series comprised 69 men and 41 women, aged 68 ± 13.2 years, with mean serum creatinine of 1.7 ± 0.8 mg/dL. Subsequently, patients classified as probable RLS according to the questionnaire underwent a systematic neurological examination. The presence of peripheral artery disease was evaluated by the ankle-brachial index (ABI).

RESULTS

The frequency of probable RLS according to the questionnaire results was 21% (17% for men and 27% for women). However, after thorough neurological examination, the diagnosis of RLS was confirmed in only 5 patients. Therefore, the overall definitive RLS frequency was 4.5% (within the prevalence reported for the general population) and was higher among women (9.7% vs 0.2%). In the remaining cases symptoms were due to leg discomfort related with other disorders. Patients with probable and improbable RLS were not significantly different in age, ABI, diabetes, and other comorbid circumstances, except for tricyclic antidepressant prescription, which was more frequent in the probable RLS group (17% vs 2%). Renal function was better in definitive RLS patients than cases classified as probable RLS by the questionnaire but not confirmed after neurological exam.

CONCLUSIONS

Although RLS can represent an early manifestation of CKD, its prevalence seems very close to that reported for the general population. Diagnostic confirmation of RLS dramatically falls after expert examination, raising the question whether, in the study of RLS cohorts, CKD has a potentially causal relationship or is a confounding factor associated with other causes of leg discomfort.

Diagnosis, comorbidities, and management of restless legs syndrome

OBJECTIVE

This narrative review describes the differential diagnosis of restless legs syndrome, and provides an overview of the evidence for the associations between RLS and potential comorbidities. Secondary causes of RLS and the characteristics of pediatric RLS are also discussed. Finally, management strategies for RLS are summarized.

METHODS

The review began with a comprehensive PubMed search for 'restless legs syndrome/Willis-Ekbom disease' in combination with the following: anxiety, arthritis, attention-deficit hyperactivity disorder, cardiac, cardiovascular disease, comorbidities, depression, end-stage renal disease, erectile dysfunction, fibromyalgia, insomnia, kidney disease, liver disease, migraine, mood disorder, multiple sclerosis, narcolepsy, neuropathy, obesity, pain, Parkinson's disease, polyneuropathy, pregnancy, psychiatric disorder, sleep disorder, somatoform pain disorder, and uremia. Additional papers were identified by reviewing the reference lists of retrieved publications.

RESULTS AND CONCLUSIONS

Although clinical diagnosis of RLS can be straightforward, diagnostic challenges may arise when patients present with comorbid conditions. Comorbidities of RLS include insomnia, depressive and anxiety disorders, and pain disorders. Differential diagnosis is particularly important, as some of the medications used to treat insomnia and depression may exacerbate RLS symptoms. Appropriate diagnosis and management of RLS symptoms may benefit patient well-being and, in some cases, may lessen comorbid disease burden. Therefore, it is important that physicians are aware of the presence of RLS when treating patients with conditions that commonly co-occur with the disorder.

The prevalence of restless legs syndrome across the full spectrum of kidney disease

STUDY OBJECTIVES

Although restless legs syndrome (RLS) is common and well recognized as an important and potentially treatable cause of sleep disruption in end-stage renal disease (ESRD), few studies have evaluated the prevalence of RLS and its impact on sleep in the non-dialysis-dependent chronic kidney disease (CKD) population. The objectives of the study were to determine the prevalence of RLS across the full spectrum of kidney disease and to assess the impact of RLS on sleep quality and daytime function.

METHODS

Five hundred patients were recruited from nephrology clinics and were stratified according to estimated glomerular filtration rate (EGFR): eGFR ≥ 60 mL/min/1.73m(2) (n = 127), CKD (eGFR < 60, not on dialysis, n = 242), and ESRD (on hemodialysis, n = 131). All subjects completed a sleep and medical history questionnaire, an RLS questionnaire, the Pittsburgh Sleep Quality Index (PSQI), and the Epworth Sleepiness Scale (ESS).

RESULTS

The prevalence of RLS did not differ among the three groups (18.9% [eGFR ≥ 60], 26% (CKD), and 26% (ESRD) p = 0.27). However, many symptoms of sleep disruption were more common in patients with RLS, and RLS was independently correlated with the PSQI score both in the full cohort (OR = 2.63, CI = 1.60-4.00, p < 0.001) and the CKD group (OR = 2.39, CI = 1.20-4.79, p = 0.014).

CONCLUSIONS

RLS is common in non-dialysis-dependent CKD patients and is an important source of sleep disruption.

Restless legs syndrome in children with chronic kidney disease

BACKGROUND

Restless legs syndrome (RLS) is considerably more common among adults with chronic kidney disease (CKD) than in the general population and is associated with increased morbidity and mortality. There is limited information on RLS in children with CKD. Failure to account for conditions that might mimic RLS can lead to overdiagnosis of this syndrome.

METHODS

In a prospective, cross-sectional study, RLS prevalence was compared between pediatric CKD patients and healthy children. RLS was assessed via a questionnaire that included exclusion of mimics. Sleep characteristics and health-related quality of life (HRQoL) were also assessed.

RESULTS

Restless legs syndrome was more prevalent in CKD patients (n = 124) than in 85 normal children (15.3 vs. 5.9 %; p = 0.04). There was no significant association between RLS and CKD stage, CKD etiology, CKD duration, and dialysis or transplant status. Children with RLS were more likely to rate their sleep quality as fairly bad or very bad (41.2 vs. 8.8 %; p = 0.003) and report using sleep medications (42.1 vs. 14.7 %; p = 0.01). RLS was associated with lower HRQoL by parent report (p = 0.03). Only five of the 19 patients (26.3 %) with CKD and RLS had discussed RLS symptoms with a healthcare provider, and only one of these patients had been diagnosed with RLS prior to this study.

CONCLUSIONS

The prevalence of RLS is increased in children with CKD and appears to be underdiagnosed. Systematic screening for RLS and sleep problems would therefore appear to be warranted in children with CKD.

Family recurrence and oligo-anuria predict uremic restless legs syndrome

OBJECTIVES

To determine clinical and laboratory predictors of restless legs syndrome (RLS) in patients with end-stage kidney disease (ESKD) undergoing long-term hemodialysis (HD).

MATERIALS AND METHODS

One hundred and sixty-two consecutive patients were assessed. History of sleep disturbances, neurological examination, clinical, and laboratory data were collected. Patients with and without RLS were compared, and a logistic regression model described the relations between independent predictors and RLS.

RESULTS

Fifty-one patients (32%) currently had RLS (RLS+). RLS+ vs RLS- patients were more frequently women (49% vs 29%, P = 0.012), had first-degree relative with RLS (22% vs 6%, P = 0.004), insomnia (59% vs 36%, P = 0.007), peripheral neuropathy (41% vs 21%, P = 0.006), and low residual diuresis (92% vs 68% with below 500 ml/24 h, P = 0.001). Low (OR = 8.71, CI = 2.27-33.41; P = 0.002) and absent (OR = 4.96, CI = 1.52-16.20; P = 0.008) residual diuresis, peripheral neuropathy (OR = 4.00, CI = 1.44-11.14; P = 0.008), and first-degree relative with RLS (OR = 3.82, CI = 1.21-12.13; P = 0.023) significantly predicted RLS in ESKD patients undergoing HD.

CONCLUSION

Positive family history for RLS together with reduced/absent residual renal function and peripheral neuropathy predicts the risk for RLS in ESKD patients undergoing HD. Longitudinal studies are warranted to correlate RLS occurrence with genetic and environmental factors.

Prevalence of sleep disturbances in children and adolescents with chronic kidney disease

Although sleep disorders are common in adults with chronic kidney disease, little is known about the prevalence of sleep problems in children and adolescents with chronic kidney disease and their relationship to health-related quality of life measurements. We performed a clinic-based survey of sleep habits and common symptoms of sleep disturbances in 159 school-aged patients with chronic kidney disease. Three patient groups of chronic kidney disease were assessed: group 1, those not on dialysis and not transplanted; group 2, those on dialysis; and group 3, those with a functioning renal allograft. Four symptom domains for sleep disorders were assessed: excessive daytime sleepiness; sleep disordered breathing; restless legs syndrome symptoms; and insufficient sleep. Patients and the parent-proxy also completed the Pediatric Quality of Life Inventory Version 4.0 Generic Core Scales questionnaire. Ninety-three (93) patients (58.5%) had symptoms of a sleep disturbance. The presence of a sleep disturbance correlated with a decrease in health-related quality of life scores that was independent of the chronic kidney disease study group or estimated glomerular filtration rate. We conclude that sleep disturbances are common throughout the spectrum of chronic kidney disease in children and adolescents and are associated with diminished health-related quality of life scores.

Restless legs syndrome--theoretical roles of inflammatory and immune mechanisms

Theories for restless legs syndrome (RLS) pathogenesis include iron deficiency, dopamine dysregulation and peripheral neuropathy. Increased prevalence of small intestinal bacterial overgrowth (SIBO) in controlled studies in RLS and case reports of post-infectious RLS suggest potential roles for inflammation and immunological alterations. A literature search for all conditions associated with RLS was performed. These included secondary RLS disorders and factors that may exacerbate RLS. All of these conditions were reviewed with respect to potential pathogenesis including reports of iron deficiency, neuropathy, SIBO, inflammation and immune changes. A condition was defined as highly-associated if there was a prevalence study that utilized an appropriate control group. Small case reports were recorded but not included as definite RLS-associated conditions. Fifty four diseases, syndromes and conditions have been reported to cause and/or exacerbate RLS. Of these, 38 have been reported to have a higher prevalence than age-matched controls, 9 have adequate sized reports and have general acceptance as RLS-associated conditions and 7 have been reported in case report form. Overall, 42 of the 47 RLS-associated conditions (89%) have also been associated with inflammatory and/or immune changes. In addition, 43% have been associated with peripheral iron deficiency, 40% with peripheral neuropathy and 32% with SIBO. Most of the remaining conditions have yet to be studied for these factors. The fact that 95% of the 38 highly-associated RLS conditions are also associated with inflammatory/immune changes suggests the possibility that RLS may be mediated or affected through these mechanisms. Inflammation can be responsible for iron deficiency and hypothetically could cause central nervous system iron deficiency-induced RLS. Alternatively, an immune reaction to gastrointestinal bacteria or other antigens may hypothetically cause RLS by a direct immunological attack on the central or peripheral nervous system.

Sleep-related movement disorders

Several movement disorders may occur during nocturnal rest disrupting sleep. A part of these complaints is characterized by relatively simple, non-purposeful and usually stereotyped movements. The last version of the International Classification of Sleep Disorders includes these clinical conditions (i.e. restless legs syndrome, periodic limb movement disorder, sleep-related leg cramps, sleep-related bruxism and sleep-related rhythmic movement disorder) under the category entitled sleep-related movement disorders. Moreover, apparently physiological movements (e.g. alternating leg muscle activation and excessive hypnic fragmentary myoclonus) can show a high frequency and severity impairing sleep quality. Clinical and, in specific cases, neurophysiological assessments are required to detect the presence of nocturnal movement complaints. Patients reporting poor sleep due to these abnormal movements should undergo non-pharmacological or pharmacological treatments.

Prevalence and clinical characteristics of restless legs syndrome in chronic kidney disease patients

OBJECTIVE

To clarify the prevalence of restless legs syndrome (RLS) in the chronic kidney disease (CKD) population and determine the relationship between severity of renal dysfunction and risk of RLS as well as the impact of the disorder on mood and sleep disturbance, we conducted a questionnaire survey followed by face-to-face interviews with Japanese CKD patients.

METHODS

We sent a questionnaire battery including demographics items, the National Institutes of Health/International RLS Study Group (IRLSSG) consensus questionnaire, the Center for Epidemiological Studies Depression Scale, and the Pittsburgh Sleep Quality Index to eligible CKD patients (n=514) and age- and sex-matched controls (n=535). Structured interviews were performed for the diagnosis of RLS.

RESULTS

The prevalence of positive RLS in the CKD subjects was significantly higher than that in the controls (3.5% vs. 1.5%, p=0.029). The proportion of renal failure (RF) in CKD subjects with RLS was significantly higher than in those without RLS, and multiple logistic regression analysis revealed that the presence of RLS symptoms was associated only with the existence of RF. In addition, the presence of both RLS and CKD was significantly associated with the presence of depression and sleep disturbance.

CONCLUSIONS

The risk of RLS in the CKD population was higher than that in the general population and increased with the progression of renal dysfunction. Additionally, the existence of RLS might play a role in an increased risk for developing depression and sleep disturbance in the CKD population.

The use of rotigotine in the treatment of restless legs syndrome

Restless legs syndrome (RLS) is a neurological disorder characterized by an urge to move the legs often accompanied by unpleasant sensations. Symptoms appear during periods of rest or inactivity, particularly in the evening and at night, and are usually relieved by movement. The prevalence of RLS among Whites is approximately 5-15%. RLS can be distinguished into primary and secondary forms. Most patients (70-80%) are affected by the primary form of RLS. The uncomfortable sensations related to RLS often cause a minimal discomfort, thus a therapeutic approach is not necessary. However, almost 3% of the general population reports to be affected by severe symptoms of RLS, requiring pharmacological treatment. Secondary forms of RLS are relieved by the remission of the underlying clinical condition. Dopamine agonists are considered to be first-line treatments for primary RLS. Rotigotine is a nonergoline dopamine agonist with selectivity for D1, D2 and D3 receptors. It is administered once a day in the form of an adhesive matrix patch. The efficacy and safety of the drug in patients with primary RLS has been demonstrated by four clinical trials using dosages of 0.5, 1, 2, 3 and 4 mg/24 h. A dose-response relationship was observed between the dosages of 0.5 and 3 mg/24 h. Side effects were usually mild, the most frequent being skin reaction at the site of patch application. More trials are ongoing and results will soon be published for the long-term (5 years) treatment of RLS with rotigotine transdermal patches. Rotigotine is a promising drug for the treatment of RLS. Its continuous delivery throughout 24 h makes it especially indicated for those cases also presenting daytime symptoms, and for those presenting the so-called augmentation syndrome after prolonged treatment with L-dopa or dopamine agonists.

Update on the management of restless legs syndrome: existing and emerging treatment options

Restless legs syndrome (RLS) is a sensorimotor disorder, characterized by a circadian variation of symptoms involving an urge to move the limbs (usually the legs) as well as paresthesias. There is a primary (familial) and a secondary (acquired) form, which affects a wide variety of individuals, such as pregnant women, patients with end-stage renal disease, iron deficiency, rheumatic disease, and persons taking medications. The symptoms reflect a circadian fluctuation of dopamine in the substantia nigra. RLS patients have lower dopamine and iron levels in the substantia nigra and respond to both dopaminergic therapy and iron administration. Iron, as a cofactor of dopamine production and a regulator of the expression of dopamine type 2-receptor, has an important role in the RLS etiology. In the management of the disease, the first step is to investigate possible secondary causes and their treatment. Dopaminergic agents are considered as the first-line therapy for moderate to severe RLS. If dopaminergic drugs are contraindicated or not efficacious, or if symptoms are resistant and unremitting, gabapentin or other antiepileptic agents, benzodiazepines, or opioids can be used for RLS therapy. Undiagnosed, wrongly diagnosed, and untreated RLS is associated with a significant impairment of the quality of life.