Restless legs syndrome in dialysis patients: a comparison between hemodialysis and continuous ambulatory peritoneal dialysis

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.

Why do we keep ignoring sex in kidney disease?

Throughout the history of nephrology, little attention has been paid to the sex and gender differences in kidney disease. This lack of awareness prevents optimal diagnosis and management of kidney disease. In today's world of precision medicine, it is imperative to appreciate the differential factors regarding gender and kidney disease. This editorial summarizes the up-to-date literature regarding sex and gender differences in kidney disease and considers areas where knowledge is incomplete and where further research is needed. We address sex-specific effects on chronic kidney disease epidemiology; risks of dialysis underdosing and medication overdosing in women; unexplained loss of female sex advantage in life expectancy during dialysis, and impact of sex on diagnosis and management of genetic kidney disease. We also aim to highlight the impact of gender on kidney health and raise awareness of disparities that may be faced by women, and transgender and gender-diverse persons when a male-model approach is used by healthcare systems. By understanding the link between sex and kidney disease, kidney specialists can improve the care and outcomes of their patients. In addition, research on this topic can inform the development of targeted prevention and intervention strategies that address the specific needs and risk factors of different populations.

To evaluate the relationship between serum magnesium and parathyroid hormone levels in peritoneal dialysis and hemodialysis patients

OBJECTS

This study aimed to determine the relationship between magnesium and PTH levels in peritoneal dialysis (PD) and hemodialysis (HD) patients.

METHODS

This cross-sectional study was performed on HD and PD patients in Kerman, Iran. After recording demographic and clinical data, the pre-dialysis levels of hemoglobin, 25-hydroxy vitamin D, ferritin, creatinine, calcium, phosphorus, albumin, PTH, and magnesium were measured for all patients. The P value of less than 0.05 was considered statistically significant.

RESULTS

Magnesium levels in PD patients were significantly higher than in HD patients (P < 0.001). The median PTH level in PD patients was significantly lower than in HD patients (P = 0.046). The correlation between PTH and serum magnesium levels was not significant in PD or HD patients. In the regression model, dialysis modality (PD or HD) was the only significant variable in determining serum magnesium levels (P = 0.005).

CONCLUSION

Magnesium is a neglected ion in peritoneal dialysis and hemodialysis patients. In dialysis centers that use a dialysate with standard magnesium concentration (0.5 mmol/L in HD and 0.75 mmol/L in PD), special attention is necessary to hypomagnesia and its complications because magnesium levels in PD patients were significantly higher than in HD patients. As the correlation between magnesium and PTH levels in both PD and HD patients were not significant, the association of high magnesium levels with low PTH in PD patients should be considered in terms of increasing the potential for adynamic bone disease. It seems that ordering serum magnesium in the routine tests of dialysis patients is necessary.

Relation of Serum Hepcidin Levels and Restless Legs Syndrome in Patients Undergoing Peritoneal Dialysis

Introduction: Restless legs syndrome is a common and severe complication in patients undergoing peritoneal dialysis (PD), which seriously affects the life quality and prognosis of patients undergoing PD. Unfortunately, there are still no effective prevention and treatment measures. Serum hepcidin was demonstrated to be related to primary restless legs syndrome (RLS), whereas there are no studies on the relationship between serum hepcidin and RLS in patients undergoing PD. We aimed to evaluate the role and function of serum hepcidin in patients undergoing PD with RLS.

Methods: A total of 51 patients undergoing PD with RLS and 102 age-and gender-matched patients undergoing PD without RLS were included. We collected the clinical data including serum hepcidin of those patients undergoing PD. We scored the severity of RLS according to the International restless leg Syndrome Research Group rating scale (IRLS). We compared the clinical characteristics of the two groups and evaluated the determinant factors of RLS by Logistic regression analysis. In addition, we evaluated the diagnostic value of serum hepcidin in patients undergoing PD with RLS by receiver operating characteristic (ROC) curve. We also analyzed the influencing factors of IRLS by multivariate linear regression analysis.

Results: The duration of PD, serum hepcidin, and calcium were found to be significantly higher in patients undergoing PD with RLS than those patients undergoing PD without RLS (P < 0.001, P < 0.001, and P = 0.002, respectively). The level of hemoglobin, albumin, and RKF were significantly lower in patients undergoing PD with RLS (P = 0.002, P = 0.042, and P < 0.001, respectively). The duration of PD [odds ratio (OR) 1.038, 95% CI: 1.017, 1.060, P < 0.001], hemoglobulin level (OR 0.969, 95% CI: 0.944, 0.995, P = 0.019), calcium level (OR 9.224, 95% CI: 1.261, 67.450, P = 0.029), albumin level (OR 0.835, 95% CI: 0.757, 0.921, P < 0.001), hepcidin level (OR 1.023, 95% CI: 1.009, 1.038, P = 0.001), and RKF (OR 0.65, 95% CI: 0.495, 0.856, P = 0.002) are independent determinant factors of RLS in patients undergoing PD. Multivariate linear regression analysis revealed that, in addition to albumin, they were also independently associated with the severity of RLS.

Conclusion: A significant relation was detected between serum hepcidin level and RLS in patients undergoing PD.

Are serum vitamin D, calcium and phosphorous associated with restless leg syndrome? A systematic review and meta-analysis

BACKGROUND

It is hypothesized that vitamin D deficiency, and calcium/phosphate imbalance could be involved in the pathophysiology of restless leg syndrome (RLS). This systematic review and meta-analysis of observational studies were carried out to reach a firm conclusion regarding the possible association between vitamin D, calcium and phosphorous levels with RLS in end-stage renal disease (ESRD) patients, other comorbidities and healthy population.

METHODS

PubMed, Scopus, ISI Web of Science, and Cochrane's library were systematically searched up to June 2020. Quality assessment of the included observational studies was performed using Newcastle-Ottawa Quality Assessment Scale. Statistical analyses were done using STATA 11.2. A P-value <0.05 were considered statistically significant.

RESULTS

A total of 36 studies involving 9590 participants were included in this systematic review and meta-analysis. We found that serum vitamin D level is significantly lower (WMD -3.39 ng/mL; 95% CI, -5.96 to -0.81; P = 0.010; I² = 86.2%) and phosphorous (SMD 0.19; 95% CI, 0.04-0.34; P = 0.011; I² = 83.6%) is significantly higher in RLS individuals compared to the non-RLS individuals. However, the mean difference of serum calcium was not significant in comparison between RLS and control groups (SMD -0.01; 95% CI, -0.19 to 0.18; P = 0.957; I² = 89.2%).

CONCLUSION

Results revealed a significant association between serum vitamin D and phosphorous with RLS. However, further prospective cohort studies and clinical trials are needed for better understanding of the relationship between these variables.

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.

Restless Legs Syndrome in Dialysis Patients: Does the Dialysis Modality Influence Its Occurrence and Severity?

Background

Restless legs syndrome (RLS) is more prevalent in chronic kidney patients than in the general population, but it is often diagnosed late and its predictors are unknown.

Purpose

To diagnose RLS in a group of chronic kidney patients on dialysis, determine its frequency and severity, compare the prevalence and severity of the condition among dialytic modalities, and identify possible predictive factors in this population.

Methods

An observational and cross-sectional study with 326 patients who had been on dialysis for more than 3 months, 241 on hemodialysis (HD) and 85 on automatic peritoneal dialysis (APD), using the criteria established by the International Study Group on RLS for the diagnosis and the RLS Rating Scale to determine its severity.

Results

RLS was diagnosed in 19.3% of the patients, 52.4% with severe or very severe forms. Patients with and without RLS did not differ in clinical and demographic characteristics and dialytic modality; however, patients on APD presented higher RLS severity compared to the HD group.

Conclusions

RLS is frequent in dialysis patients and occurs predominantly in its most severe forms; the dialytic modality seems to have no influence on its occurrence; however, it is more severe in patients on APD.

The Ferumoxytol for Anemia of CKD Trial (FACT)-a randomized controlled trial of repeated doses of ferumoxytol or iron sucrose in patients on hemodialysis: background and rationale

Background

Iron deficiency anemia (IDA) is a common manifestation of chronic kidney disease (CKD), affecting most patients on hemodialysis and imposing a substantial clinical burden. Treatment with iron supplementation increases hemoglobin levels and can reduce the severity of anemia in patients with CKD. While correcting anemia in these patients is an important therapeutic goal, there is a lack of long-term trials directly comparing intravenous iron therapies in patients with CKD receiving hemodialysis.

Methods/Design

The Ferumoxytol for Anemia of CKD Trial (FACT) is a 13-month, open-label, randomized, multicenter, international, prospective study with 2 substudies. Entry criteria for the main study include adults with IDA (defined as hemoglobin <11.5 g/dL [<115.0 g/L] and a transferrin saturation <30%), serum ferritin <800 ng/mL (<1798 pmol/L), and receiving hemodialysis for ≥3 months. Patients are randomized to receive ferumoxytol (1.02 g over 2 doses) or iron sucrose (1.0 g over 10 doses) during the initial 5-week treatment period. Those with persistent/recurrent IDA over the 11-month observation period will receive additional 5-week treatment periods, as appropriate. The primary efficacy endpoint of the main study is the mean change in hemoglobin from Baseline to Week 5 for each treatment period. The secondary efficacy endpoints include the mean change in transferrin saturation from Baseline to Week 5 and the proportion of patients with a hemoglobin increase of ≥1.0 g/dL at any time from Baseline to Week 5. Safety will be assessed through an examination of the adverse event profile over the course of the study. An “oxidative stress” substudy in approximately 100 patients will assess the effects of treatment on biomarkers of oxidative stress/inflammation during the initial 5-week treatment period, and a magnetic resonance imaging substudy in approximately 70 patients will assess the potential for iron deposition in target tissues over 24 months.

Discussion

FACT fulfills the need for a long-term comparative trial in patients with IDA and CKD receiving hemodialysis. The efficacy and safety results will provide useful information for guiding therapy in this population. Two hundred ninety-six patients have been enrolled, and completion of the main study is expected soon.

Trial registration

ClinicalTrials.gov identifier: NCT01227616 (registered October 22, 2010); EudraCT number: 2010-022133-28

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 hemodialysis patients in Iran

Restless legs syndrome (RLS) is a common sleep disorder that can present secondary to medical conditions such as renal failure. This study aimed to evaluate RLS frequency and its related factors in chronic renal failure patients treated with hemodialysis. In a cross-sectional design, 163 patients with chronic renal failure were consecutively enrolled from hemodialysis center at Rasool-Akram hospital. Demographics, clinical and laboratory data were recorded. Patients were screened for presence and severity of RLS according to the four International Restless Legs Syndrome Group (IRLSSG) diagnostic criteria and severity scale. Patients with and without RLS were compared using SPSS statistical software (Version 16.0). Sixty-one patients (37.4 %) were diagnosed with RLS. Mean age in RLS group was significantly higher (65.2 ± 9.3 years) than RLS-negative group (59.0 ± 14.7 years; P = 0.004). Serum creatinine level was significantly higher in patients with RLS (7.6 ± 2.1 mg/dl vs. 6.7 ± 1.8 mg/dl; P = 0.009). Glomerular filtration rate in RLS patients was lower than other patients (9.2 ± 3.1 ccs/min vs. 11.6 ± 4.8 ccs/min; P = 0.0001). Patients with RLS had shorter sleep duration, and higher incidence of insomnia, daytime sleepiness, and sedative-hypnotic medication usage (P < 0.05). There was no significant difference between RLS-positive and RLS-negative patients in terms of renal failure pathology, dialysis frequency per week, dose of dialysis, duration of dialysis, renal transplantation, and history of diabetes and hypertension. Hemodialysis patients have a high prevalence of RLS which deserves special attention and specific treatment.

Current trends in the management of uremic restless legs syndrome: a systematic review on aspects related to quality of life, cardiovascular mortality and survival

Restless legs syndrome (RLS) affects almost one out of three end-stage renal disease patients. This review assesses the current treatment options for uremic RLS and the potential benefits of those treatments on quality of life parameters, cardiovascular mortality and survival. A systematic review was conducted searching PubMed and Scopus by using the Cochrane and PRISMA guidelines. Fourteen studies met the inclusion criteria in which the international RLS study group criteria were used as the primary diagnostic tool. Both pharmacological and non-pharmacological approaches were found to reduce the severity of uremic RLS symptoms. Only four studies reported changes on aspects related to quality of life while those changes were also associated with health benefits that resulted in reduced cardiovascular risk. The severity of uremic RLS symptoms can be ameliorated by using dopamine agonists and gabapentin, intravenous iron, exercise or supplementation with vitamins C and E, although some of those treatment benefits may be transient. There is a lack of strong evidence regarding the effects of the pharmacological approaches on quality of life and cardiovascular survival and mortality. In contrast exercise has been proven beneficial in both reducing the RLS symptoms' severity score and improving the quality of life.

Epidemiology, impact, and treatment options of restless legs syndrome in end-stage renal disease patients: an evidence-based review

Restless legs syndrome (RLS) (or Willis-Ekbom disease) is a neurological disorder with high prevalence among the end-stage renal disease population. This is one of the most predominant types of secondary RLS, and it is called uremic RLS. Despite the fact that uremic RLS has been less studied compared to idiopathic RLS, recent studies now shed light in many aspects of the syndrome including clinical characteristics, impact, epidemiology, and treatment options. The current review discusses the above topics with special emphasis given on the management of uremic RLS, including the management of symptoms that often appear during a hemodialysis session. Uremic RLS symptoms may be ameliorated by using pharmacological and nonpharmacological treatments. Evidence so far shows that both approaches may be effective in terms of reducing the RLS symptom's severity; nevertheless, more research is needed on the efficiency of treatments for uremic RLS.

A single-blind randomized controlled trial to evaluate the effect of 6 months of progressive aerobic exercise training in patients with uraemic restless legs syndrome

BACKGROUND

Uraemic restless legs syndrome (RLS) affects a significant proportion of patients receiving haemodialysis (HD) therapy. Exercise training has been shown to improve RLS symptoms in uraemic RLS patients; however, the mechanism of exercise-induced changes in RLS severity is still unknown. The aim of the current randomized controlled exercise trial was to investigate whether the reduction of RLS severity, often seen after training, is due to expected systemic exercise adaptations or it is mainly due to the relief that leg movements confer during exercise training on a cycle ergometer. This is the first randomized controlled exercise study in uraemic RLS patients.

METHODS

Twenty-four RLS HD patients were randomly assigned to two groups: the progressive exercise training group (n = 12) and the control exercise with no resistance group (n = 12). The exercise session in both groups included intradialytic cycling for 45 min at 50 rpm. However, only in the progressive exercise training group was resistance applied, at 60-65% of maximum exercise capacity, which was reassessed every 4 weeks to account for the patients' improvement. The severity of RLS symptoms was evaluated using the IRLSSG severity scale, functional capacity by a battery of tests, while sleep quality, depression levels and daily sleepiness status were assessed via validated questionnaires, before and after the intervention period.

RESULTS

All patients completed the exercise programme with no adverse effects. RLS symptom severity declined by 58% (P = 0.003) in the progressive exercise training group, while a no statistically significant decline was observed in the control group (17% change, P = 0.124). Exercise training was also effective in terms of improving functional capacity (P = 0.04), sleep quality (P = 0.038) and depression score (P = 0.000) in HD patients, while no significant changes were observed in the control group. After 6 months of the intervention, RLS severity (P = 0.017), depression score (P = 0.002) and daily sleepiness status (P = 0.05) appeared to be significantly better in the progressive exercise group compared with the control group.

CONCLUSION

A 6-month intradialytic progressive exercise training programme appears to be a safe and effective approach in reducing RLS symptom severity in HD patients. It seems that exercise-induced adaptations to the whole body are mostly responsible for the reduction in RLS severity score, since the exercise with no applied resistance protocol failed to improve the RLS severity status of the patients.