Efficacy of vitamins C, E, and their combination for treatment of restless legs syndrome in hemodialysis patients: a randomized, double-blind, placebo-controlled trial

BackgroundRestless legs syndrome (RLS) is a common disorder in hemodialysis patients that leads to insomnia and impaired quality of life. Because high oxidative stress has been implicated in the pathogenesis of RLS, we sought to evaluate the efficacy of vitamins C and E and their combination in reducing the severity of RLS symptoms in hemodialysis patients in this randomized, double-blind, placebo-controlled, four-arm parallel trial.MethodsSixty stable hemodialysis patients who had all four diagnostic criteria for RLS developed by the International Restless Legs Syndrome Group with no acute illness or history of renal stone were randomly allocated to four fifteen-patient parallel groups to receive vitamin C (200 mg) and vitamin E (400 mg), vitamin C (200 mg) and placebo, vitamin E (400 mg) and placebo, and double placebo daily for eight weeks. International Restless Legs Scale (IRLS) scores were measured for all patients at baseline and at the end of treatment phase. The primary outcome was absolute change in IRLS sum score from baseline to the end of treatment phase.ResultsMeans of IRLS sum score decreased significantly in the vitamins C and E (10.3 ± 5.3, 95% CI: 7.4–13.3), vitamin C and placebo (10 ± 3.5, 95% CI: 8.1–11.9), and vitamin E and placebo groups (10.1 ± 6, 95% CI: 6.8–13.5) compared with the double placebo group (3.1 ± 3, 95% CI: 1.5–4.8), (P < 0.001); however, no differences were observed between these treatment groups.ConclusionsVitamins C and E and their combination are safe and effective treatments for reducing the severity of RLS in hemodialysis patients over the short-term.     

Effect of pramipexole on RLS symptoms and sleep: a randomized, double-blind, placebo-controlled trial

BackgroundPatients with Restless Legs Syndrome (RLS) often seek treatment because of sleep problems related to nocturnal symptoms. Our goal was to test the ability of pramipexole to improve sleep in RLS patients and to reconfirm its efficacy for primary RLS symptoms.MethodsAdults with moderate or severe RLS were randomized to receive placebo or pramipexole (flexibly titrated from 0.25 to 0.75 mg), 2–3 h before bedtime for 12 weeks. The co-primary outcome measures were change in Medical Outcomes Study (MOS) sleep disturbance score and International RLS Study Group Rating Scale (IRLS) score at 12 weeks.ResultsThe intent-to-treat population included 357 patients: 178 received pramipexole and 179 received placebo. At 12 weeks, the adjusted mean change from baseline was greater for pramipexole (vs. placebo) for IRLS score (−13.4 ± 0.7 vs. −9.6 ± 0.7) and MOS sleep disturbance score (−25.3 ± 1.5 vs. −16.8 ± 1.5) (p ⩽ 0.0001; ANCOVA). Responder rates (clinical and patient global impression and IRLS) were also significantly higher in the pramipexole group. RLS-QOL score was improved over placebo at Week 12 (p < 0.01) as were MOS sleep adequacy (p = 0.0008) and quantity (p = 0.08) scores. Nine percent of patients in each group withdrew because of adverse events.ConclusionsPramipexole is effective and well-tolerated for RLS and related sleep disturbance.     

Clinical efficacy of ropinirole for restless legs syndrome is not affected by age at symptom onset

ObjectiveTo determine whether clinical response to the dopamine agonist, ropinirole, in the treatment of primary restless legs syndrome (RLS), depends upon the age-at-onset of RLS symptoms.MethodsPooled data from four 12-week, randomized, double-blind, placebo-controlled studies of ropinirole in patients with moderate-to-severe primary RLS were analyzed post hoc. The relationship between age-at-onset and response to treatment, based on change from the baseline International Restless Legs Syndrome Study Group (IRLSSG) rating scale (the International Restless Legs Scale [IRLS]) total score and the proportion of responders (rated ‘much’/‘very much’ improved) on the Clinical Global Impression–Improvement (CGI-I) scale, was explored.ResultsThe range of age-at-onset of RLS symptoms was 2–75 years. No relationship was observed between the age-at-onset of RLS symptoms and baseline IRLS total score (correlation r = −0.06), and between dose administered at Week 12 last observation carried forward (LOCF) and age-at-onset (r = −0.04). The age-at-onset by treatment interaction was non-significant (P = 0.952 for the IRLS and P = 0.716 for the CGI-I scale), indicating there was no significant relationship between age-at-onset and the magnitude of ropinirole treatment effect.ConclusionsThese data suggest that ropinirole provides effective relief of symptoms, regardless of age at RLS symptom onset.     

Investigating the response to intravenous iron in restless legs syndrome: an observational study

ObjectiveTo investigate the effect of intravenous (IV) iron (500 mg ferric carboxymaltose [FCM] as a single dose) on restless legs syndrome (RLS) severity on a day-to-day basis.MethodsTwenty patients with RLS and absolute or functional iron deficiency or low normal serum ferritin (<45 μg/l) were included. Change of RLS severity was evaluated using the International RLS severity scale (IRLS) and the RLS-severity diary (RLS-SD) which evaluates symptom severity over a 6-h period on an 11-point numerical Likert scale, four times a day.ResultsTwelve patients reported that IV FCM improved RLS (“responders”). IRLS score decreased from 30.1 (±5.9) to 23.07 (±9.5) (p = 0.001) in the whole group and from 28.3 (±6.1) to 18.3 (±8.0) (p = 0.002) in the responder group three weeks after IV FCM treatment. A clinically relevant effect of IV iron on RLS severity could be seen as early as day eight. The responder group differed from the non-responder group in tendency by being younger (p = 0.064), having a lower serum ferritin level at baseline (p = 0.097), and presenting a lower number of comorbid conditions.ConclusionsFCM led to a considerable improvement in RLS in the responder group within about one week. These findings are clinically relevant, especially for patients with severe RLS symptoms and iron deficiency, since a change or uptitration of RLS-specific medication can be avoided or postponed in these patients due to the rapid response to IV FCM treatment.     

Randomized,placebo-controlled trial of ferric carboxymaltose in restless legs syndrome patients with iron deficiency anemia

ObjectiveIntravenous ferric carboxymaltose (FCM) has been shown to be efficacious in treating restless legs syndrome (RLS) symptoms in non-anemic patients. The aim of this study was to evaluate the effectiveness of FCM in treating RLS symptoms in patients who also had an iron deficiency anemia (IDA).MethodsThis is a randomized, double-blinded, placebo-controlled study. Subjects with RLS and IDA were enrolled. Subjects received an infusion of either 1500 mg FCM or placebo in Phase I. The primary outcomes were a change-from-baseline at week six on the International Restless Legs Syndrome Study Group scale (IRLS). Phase II of the study involved long-term (52 weeks) follow-up, for those who responded to treatment in the prior phase, with the potential for further treatment if symptoms returned.ResultsWe enrolled 29 RLS patients with IDA (15 FCM and 14 placebo). At week six post-infusion, FCM compared to placebo group showed significant improvement from baseline in IRLS score (−13.47 ± 7.38 vs. 1.36 ± 3.59). Among secondary outcome variables, quality of sleep showed significant improvement from baseline in the FCM group. 61% of subjects remained off RLS medications at the Phase II, week-52 endpoint. There were no serious adverse events observed in the study.ConclusionThe study showed significant efficacy and safety of FCM 1500 mg treatment both in the short term (6 weeks) and long term (52 weeks) in RLS patients with IDA.     

Evaluation of oral iron treatment in pediatric restless legs syndrome (RLS)

ObjectiveWe conducted a retrospective chart review of children with restless legs syndrome (RLS) to evaluate the efficacy of oral iron treatment, which was administered open-label during the course of clinical care. In addition, we provided detailed clinical information about RLS in this pediatric cohort.Patients and methodsThe study included 30 consecutive Japanese children with RLS who visited the Pediatric Sleep Clinic at Osaka University Hospital, and consisted of 17 boys and 13 girls, aged 2–14 years (mean ± SD, 6.5 ± 2.8). All-night polysomnography was performed in 18 patients and serum ferritin levels were measured in all the patients. After the diagnosis of RLS, iron was administered at doses between 1.6 and 7.8 mg/kg/day (3.2 ± 1.3). Serum ferritin was re-evaluated 3–6 months after iron treatment, or when RLS symptoms had disappeared.ResultsThe patient age at onset of RLS symptoms ranged from six months to 13 years (4.3 ± 3.6). A positive family history was recognized in 19 children (63.3%). Serum ferritin levels before therapy were 9–62 ng/ml (26.6 ± 12.8) and oral iron supplementation was reported to be highly effective in 17 children, effective in 10, and ineffective in three. The serum ferritin level at follow-up was 23–182 ng/ml (83.5 ± 49.8). The onset of treatment effect was within approximately three months.ConclusionsIron treatment could be effective in Japanese pediatric RLS.     

Relation of the International Restless Legs Syndrome Study Group rating scale with the Clinical Global Impression severity scale,the restless legs syndrome 6-item questionnaire,and the restless legs syndrome-quality of life questionnaire

BackgroundThe SP790 study (ClinicalTrials.gov, NCT00136045) showed benefits of rotigotine over placebo in improving symptom severity of restless legs syndrome (RLS), also known as Willis-Ekbom disease, on the International Restless Legs Syndrome Study Group rating scale (IRLS), Clinical Global Impression item 1 (CGI-1), RLS 6-item questionnaire (RLS-6), and the RLS-quality of life questionnaire (RLS-QoL) in patients with moderate to severe idiopathic RLS. To provide clinical context for the IRLS and to guide the choice of assessment scales for RLS studies, our post hoc analysis of SP790 data evaluated associations between the IRLS and the CGI-1, IRLS and RLS-6, and the IRLS and RLS-QoL.MethodsScale associations were analyzed at baseline and at the end of maintenance (EoM) using data from the safety set (rotigotine and placebo groups combined [n = 458]). Changes from baseline to EoM in IRLS score vs comparator scale scores also were analyzed.ResultsThere was a trend towards increasing IRLS severity category with increasing CGI-1, RLS-6, and RLS-QoL score. Pearson product moment correlation coefficients showed correlations between IRLS and comparator scale scores at baseline and EoM as well as correlations for change from baseline to EoM.ConclusionCorrelations between the IRLS and comparator scales were substantial. These data indicate that the IRLS is clinically meaningful. The IRLS and CGI-1 are generally sufficient to evaluate the overall severity and impact of RLS symptoms in clinical trials.     

Is preeclampsia associated with restless legs syndrome?

ObjectiveRestless legs syndrome (RLS) is a common neurologic disorder. Secondary RLS includes pregnancy and iron deficiency. Prevalence of RLS in pregnancy ranges from 11% to 27%. We aimed to assess the frequency and characteristics of RLS in pregnancy in a Peruvian population and to evaluate the possible pregnancy or delivery complications due to RLS.MethodsWe assessed 218 consecutive expectant mothers at the inpatient clinic of the Hospital San Bartolome in Lima, Peru. Assessment was performed by using the standard diagnostic criteria for RLS and by using a clinical and diagnostic interview. Questionnaires for RLS severity, idiopathic RLS (IRLS), and excessive daytime sleepiness (EDS) according to the Epworth sleepiness scale (ESS) were used. Blood examination was performed for hemoglobin and hematocrit. For comparison, RLS patients were matched for age and body mass index (BMI) with pregnant women without RLS.ResultsOut of 218 patients, 40 (18.4%) fulfilled diagnostic criteria for RLS. In RLS patients, prophylactic iron supplementation therapy during pregnancy was less frequently taken (P = .02). Pregnant women with RLS had a higher ESS score than pregnant controls (10.6 +/− 3.1 vs 7.6. +/− 3.6; P < .001). Preeclampsia was more frequent in RLS (7/40 vs 1/39; P = .03).ConclusionsIn our study, RLS was frequent in pregnant Peruvian women, especially in those without prophylactic iron supplementation. RLS patients described more EDS. Preeclampsia was more common in RLS. Our study is the first study to indicate a possible association between RLS and preeclampsia.     

Clinical efficacy and safety of intravenous ferric carboxymaltose treatment of pediatric restless legs syndrome and periodic limb movement disorder

BackgroundIron supplementation is the most commonly considered treatment option for children with restless legs syndrome (RLS) or periodic limb movement disorder (PLMD); however, there is a scarcity of evidence on the effectiveness of intravenous preparations. In this study, we evaluated the effectiveness and tolerability of intravenous ferric carboxymaltose (IV FCM) on clinical symptoms and iron indices in children with RLS or PLMD.MethodsThis was a single-center retrospective data analysis. Children with a diagnosis of RLS or PLMD, who underwent a single infusion of IV FCM, were included. Clinical Global Impression (CGI) Scale scores, serum ferritin, and serum iron profile at baseline and after eight weeks post infusion were obtained. Adverse effects were assessed.ResultsThirty-nine children received IV FCM, 29 with RLS and 10 with PLMD. Pre-infusion CGI-Severity revealed moderate illness, with post-infusion CGI-Improvement between “very much improved” and “much improved”. Ferritin increased from 14.6 μg/L ± 7.01 to 112.4 μg/L ± 65.86 (p < 0.00001), together with improvements in iron, total iron binding capacity, and transferrin levels from baseline to post-treatment. When compared to children with RLS, those with PLMD had a similar improvement in clinical symptoms and laboratory parameters. Seven subjects (14.3%) experienced one or two adverse events; all were mild.ConclusionsChildren with RLS and PLMD responded to IV iron supplementation with improvement in both clinical severity and laboratory parameters. Treatment was well tolerated. Although larger, randomized-controlled trials are needed, IV FCM appears to be a promising alternative to oral iron supplementation for the treatment of pediatric RLS or PLMD.     

Restless legs syndrome, sleep impairment, and fatigue in chronic obstructive pulmonary disease

ObjectiveTo investigate the frequency of factors associated with restless legs syndrome (RLS) in patients with chronic obstructive pulmonary disease (COPD).MethodsRLS diagnosis was investigated (International RLS Study Group, IRLSSG) and severity was assessed (IRLS rating scale) in 104 consecutive COPD patients (age 69.1 ± 8). Other measures were dyspnea severity (Modified Medical Research Council, MMRC), sleep quality (Pittsburgh Sleep Quality Index, PSQI), daytime somnolence (Epworth Sleepiness Scale, ESS), depressive symptoms (Beck Depression Inventory, BDI-II), and fatigue (Fatigue Severity Scale, FSS). Laboratory values included hemoglobin, ferritin, creatinine, and fibrinogen.ResultsThirty-two patients (30.8%) were diagnosed with RLS (65.6% women), which was moderate/severe (IRLS >11) in 26 (81.3%). RLS symptoms started after age 40 in most patients (93.3%). RLS patients had poorer sleep quality (PSQI >5 = 59.6%; p = 0.002), worse fatigue (FSS >27 = 51%; p = 0.005), and more depressive symptoms (BDI-II >10 = 14.4%; p = 0.005). Patients with RLS also presented more severe dyspnea (p = 0.009) and lower creatinine levels (p = 0.005). Overall, fatigue severity was correlated with older age (p = 0.001); level of dyspnea was positively correlated with PSQI and FSS (p < 0.005) and negatively correlated with ferritin (p = 0.03) and creatinine (p = 0.005), and PSQI scores correlated positively with FSS (p < 0.005) and negatively with ferritin (p = 0.005) and creatinine (p = 0.02). Quality of sleep was independently predicted by dyspnea severity and creatinine and fatigue by age and depression.ConclusionRLS is common in COPD. Patients with RLS have low creatinine, poorer quality of sleep, and more fatigue and depressive symptoms. RLS symptom severity is correlated to lower ferritin and severity of dyspnea.     

Outcomes of long-term iron supplementation in pediatric restless legs syndrome/periodic limb movement disorder (RLS/PLMD)

ObjectivesRestless legs syndrome (RLS) and periodic limb movement disorder (PLMD) are thought to center around a genetically mediated sensitivity to iron insufficiency. Previous studies have shown the effectiveness of short-term iron therapy in children with low iron storage. Little is known, however, about long-term iron treatment in children with RLS and PLMD. Therefore, we performed this study to assess the long-term effect of iron therapy in children with RLS and PLMD.MethodsA retrospective chart review was performed for children who met the following criteria: A) diagnosed as having either RLS or PLMD, B) started on iron supplementation, C) followed up for >2 years in a sleep clinic. Baseline values for iron, ferritin, and periodic limb movement of sleep index (PLMS index) were defined in the three months leading up to the initiation of iron therapy. Values were also computed for follow-up periods of 3–6 months, 1–2 years, and >2 years. Serum iron and ferritin levels and PLMS index were compared between baseline and all subsequent follow-ups.ResultsIn total, 105 patients met inclusion criteria, of whom 64 were diagnosed with PLMD alone, seven with RLS alone, and 35 with both RLS and PLMD. The average age was 10.2 ± 5.3 years. Compared to the baseline (27.4 ± 12.1 ng/ml), the average ferritin values at 3–6 months (45.62 ± 21.2 ng/ml, p < 0.001, n = 34), 1–2 years (52.0 ± 48.3 ng/ml, p <0.001, n = 63), and >2 years (54.7 ± 40.5 ng/ml, p <0.001, n = 67) were all significantly increased. Inversely, compared to baseline (21 ± 27.0/h, n = 66), PLMS index values at 3–6 months (7.5 ± 9.5/h p < 0.05, n = 11), 1–2 years (6.9 ± 8.9/h, p <0.001, n = 29), and >2 years (10 ± 14.5/h, p <0.001, n = 31) were all significantly decreased. No significant change in serum iron levels was noted at any time point.ConclusionWhile retrospective in nature, this study demonstrates a sustained improvement in PLMS index and maintenance of adequate ferritin levels >2 years after iron therapy initiation in our RLS/PLMD cohort with a long-term follow-up. Iron therapy appears to lead to long-lasting improvements in children with RLS/PLMD.     

One year open-label safety and efficacy trial with rotigotine transdermal patch in moderate to severe idiopathic restless legs syndrome

BackgroundLong-term efficacy and tolerability data are not yet available for patch formulations of dopamine agonists in restless legs syndrome.MethodsEfficacy and safety of rotigotine (0.5–4 mg/24 h), formulated as a once-daily transdermal system (patch), were investigated in an open extension (SP710) of a preceding 6-week placebo-controlled trial (SP709, 341 randomized patients) in patients with idiopathic restless legs syndrome. For efficacy assessment the international RLS severity scale (IRLS), the RLS-6 scales, the clinical global impressions (CGI) and the QoL-RLS questionnaire were administered. In addition, long-term tolerability and safety were assessed.ResultsOf 310 patients who finished the controlled trial, 295 (mean age 58 ± 10 years, 66% females) with a mean IRLS score of 27.8 ± 5.9 at baseline of SP709 were included. We report results after one year of this ongoing long-term trial. Two hundred twenty patients (retention rate = 74.6%) completed the 12-month follow-up period. The mean daily dose was 2.8 ± 1.2 mg/24 h with 4 mg/24 h (40.6%) being the most frequently applied dose; 14.8% were sufficiently treated with 0.5 or 1.0 mg/24 h. The IRLS total score improved by −17.4 ± 9.9 points between baseline and end of Year 1 (p < 0.001). The other measures of severity, sleep satisfaction and quality of life supported the efficacy of rotigotine (p < 0.001 for pre-post-comparisons of all efficacy variables). The tolerability was described as “good” or “very good” by 80.3% of all patients. The most common adverse events were application site reactions (40.0%), which led to withdrawal in 13.2%. Further relatively frequent adverse events were nausea (9.5%) and fatigue (6.4%). Two drug-related serious adverse events, nausea and syncope, required hospitalization. Symptoms of augmentation were not reported by the patients.ConclusionRotigotine provided a stable, clinically relevant improvement in all efficacy measures throughout one year of maintenance therapy. The transdermal patch was safe and generally well tolerated by the majority of patients. Comparable to any transdermal therapy, application site reactions were the main treatment complication.     

A randomized,double-blind, 6-week,dose-ranging study of pregabalin in patients with restless legs syndrome

ObjectiveThis study evaluated the dose-related efficacy and safety of pregabalin in patients with idiopathic restless legs syndrome (RLS).MethodsThis six-arm, double-blind, placebo-controlled, dose–response study randomized patients (N = 137) with moderate-to-severe idiopathic RLS in an equal ratio to placebo or pregabalin 50, 100, 150, 300, or 450 mg/day. The dose–response was characterized using an exponential decay model, which estimates the maximal effect (E_max) for the primary endpoint, the change in the International Restless Legs Study Group Rating Scale (IRLS) total score from baseline to week 6 of treatment. Secondary outcomes included Clinical Global Impressions-Improvement Scale (CGI-I) responders, sleep assessments, and safety.ResultsThe separation of treatment effect between placebo and pregabalin began to emerge starting at week 1 which continued and increased through week 6 for all dose groups. The IRLS total score for pregabalin was dose dependent and well characterized for change from baseline at week 6. The model estimated 50% (ED₅₀) and 90% (ED₉₀) of the maximal effect in reducing RLS symptoms that occurred at pregabalin doses of 37.3 and 123.9 mg/day, respectively. A higher proportion of CGI-I responders was observed at the two highest doses of pregabalin (300 and 450 mg/day) versus placebo. Dizziness and somnolence were the most common adverse events and appeared to be dose-related.ConclusionsIn this 6-week phase 2b study, pregabalin reduced RLS symptoms in patients with moderate-to-severe idiopathic RLS. The symptom reduction at week 6 was dose-dependent with 123.9 mg/day providing 90% efficacy. Pregabalin was safe and well tolerated across the entire dosing range.     

Efficacy and safety of dopamine agonists in restless legs syndrome

ObjectiveRestless legs syndrome (RLS) is a common neurological disorder causing considerable impairment to daily living. This article is an overview of a comprehensive Cochrane meta-analysis on the efficacy and safety of dopamine agonists (DAs), the first-line treatment of RLS.MethodsCENTRAL, MEDLINE, EMBASE, PsycINFO, and CINAHL databases were searched for double-blind randomized controlled trials (RCTs) of DAs vs placebo.ResultsThirty-five placebo-controlled RCTs (total number of patients = 6954) were eligible. The likelihood of bias was considered to be low. The mean treatment duration of the RCTs was 10.3 (standard deviation 7.3) weeks, with treatment durations up to seven months. Overall, DAs showed a moderate improvement in the International RLS Severity Scale score (mean difference ?5.7 points [95% confidence interval, CI, ?6.7 to ?4.7; P < 0.00001]) and the Clinical Global Impression-Improvement response (risk ratio 1.44 [95% CI 1.34–1.54; P < 0.00001]) compared with placebo. Periodic limb movements decreased by ?22.38/h (95% CI ?27.8 to ?16.9; P < 0.00001) for DAs compared with placebo. Sleep quality and disease-specific quality of life increased slightly to moderately. Safety data confirmed the established safety characteristics of DAs. Augmentation, a specific side-effect of dopaminergic treatment of RLS, was not assessed adequately.ConclusionsThis meta-analysis showed that DAs have moderate efficacy in the treatment of RLS. Actively controlled and long-term studies are still lacking. Large-scale comparative studies are needed to identify the most efficient treatments for this chronic disorder.     

The severity range of restless legs syndrome (RLS) and augmentation in a prospective patient cohort: Association with ferritin levels

ObjectivesThe aim of the study was to prospectively examine all patients with a diagnosis of RLS consulting a sleep disorders clinic and to assess RLS severity and augmentation and their associations, including ferritin levels.MethodsPatients were stratified into patients with RLS as ancillary diagnosis, RLS sufferers without current augmentation and RLS sufferers with current augmentation. Work-up included RLS severity scales and blood biochemical variables including indices of iron metabolism.ResultsIn an 18-month period, 302 patients with RLS (183 women, 119 men; mean age, 59.1 ± 13.7 years) were recruited. RLS was considered idiopathic in 291 patients (96.4%). Most patients (240, 79.5%) were RLS sufferers, whereas the remaining 62 (20.5%) had RLS as ancillary diagnosis. Nineteen out of 162 patients treated with dopaminergic agents (11.7%) had current augmentation. Almost one-third of all patients (31.1%) had ferritin levels <50 μg/l. Patients with an ancillary diagnosis of RLS had higher ferritin levels than RLS sufferers without current augmentation. The lowest ferritin levels were present in RLS sufferers with current augmentation 132.8 ± 98.0 μg/l vs. 100.6 ± 84.5 μg/l vs. 55.8 ± 43.6 μg/l; p = 0.002). Patients with augmentation did not differ from non-augmented patients regarding age, gender, RLS etiology, presence of previous augmentation, or any other documented comorbidity (p > 0.05).ConclusionThe severity spectrum of RLS in this clinical cohort ranged from the ancillary diagnosis of RLS to augmented RLS. There was an inverse correlation between RLS severity and ferritin levels. Patients with current augmentation had the lowest ferritin levels. Our data further strengthen a putative role of low iron stores as a potential aggravator of idiopathic RLS. Moreover, low ferritin might represent a potential biomarker of RLS augmentation under dopaminergic therapy.     

Prevalence of restless legs syndrome in a Japanese elderly population

ObjectiveTo estimate the prevalence of restless leg syndrome (RLS) in elderly Japanese people by means of a population-based survey of subjects aged ≥65 years.BackgroundStudies conducted worldwide have revealed large variations in the prevalence of RLS among different populations. However, few studies have been done in Japan.MethodsA population-based survey was carried out from 2003 to 2006 through a local healthcare project in the small town of Ajimu in a rural area of southern Japan. A Japanese translation of the questionnaire covering the four features of RLS as defined by the International RLS Study Group in 1995 was used to confirm the diagnosis of RLS. All participants aged ≥65 years were invited to fill out the questionnaire. Subjects with positive results underwent face-to-face interviews.ResultsA total of 1251 persons (men, 35%; mean age, 75.0 ± 6.1 years) answered the questionnaire. Of these 1251 participants, 70 (5.6%) (men, 20%; mean age, 75 ± 4.9 years) answered the questions on RLS positively. Face-to-face interviews and examination confirmed the diagnosis of RLS in 12 subjects. Therefore the overall prevalence of RLS in the elderly Japanese population was estimated at 0.96%, with a higher prevalence in women (1.23%) than in men (0.46%).ConclusionThe overall prevalence of RLS among inhabitants of Ajimu aged ≥65 years is 0.96%. Most of the subjects identified were women. The prevalence of RLS is lower in Japan than in studies conducted in European and North American populations.     

Difference in background factors between responders to gabapentin enacarbil treatment and responders to placebo: pooled analyses of two randomized,double-blind,placebo-controlled studies in Japanese patients with restless legs syndrome

ObjectiveRestless legs syndrome (RLS) is a sensorimotor disorder that is characterized by uncomfortable and unpleasant sensations mainly in the legs. Two placebo-controlled studies (Phase II/III and post-marketing) in Japanese patients with RLS failed to demonstrate the efficacy of gabapentin enacarbil (GE) 600 mg in the change from baseline in International Restless Legs Syndrome Rating Scale (IRLS) score at the end of the treatment period. The high response to placebo is thought to be a possible reason why the post-marketing study failed. The objectives of these post hoc analyses were to determine potential predictive factors associated with improvement in IRLS score with GE treatment and to identify subgroups with higher placebo responses.MethodsWe combined data from the two Japanese studies and analyzed change from baseline in IRLS score in the pooled population and subgroups defined by several patient characteristics. Moreover, we calculated the variable importance of each factor and performed predictive enrichment analysis to identify an enrichable subpopulation with greater improvement by GE treatment.ResultsThe post hoc analyses suggested that higher baseline IRLS score (≥21) and higher body mass index (≥25 kg/m²) were associated with higher placebo responses. On the other hand, positive family history of RLS, prior use of dopaminergic receptor agonists, and higher baseline ferritin level (≥50 ng/mL) were associated with higher responses to GE.ConclusionsOur results suggest that patients with typical idiopathic RLS characteristics, including positive family history and no low ferritin level, would be expected to derive the greatest benefits from GE treatment.     

Efficacy of ferric carboxymaltose (FCM) 500 mg dose for the treatment of Restless Legs Syndrome

IntroductionThere have been four randomized, placebo-controlled, double-blinded studies of intravenous (IV) iron in Restless Legs Syndrome (RLS), all of which delivered a final total dose of 1000 mg of iron. The purpose of this study was to evaluate effects of a lesser total dose (500 mg of iron).MethodsSubjects with idiopathic RLS were enrolled in a randomized, double-blinded, placebo-controlled study. Subjects received either 500 mg ferric carboxymaltose (FCM) or placebo as a single infusion (Phase I). Subjects who were previously on medication were off any RLS medications for at least two weeks prior to baseline assessment. The primary outcome variable was a change-from-baseline at week six on the International RLS Severity Scale (IRLSS) and a subject-completed Visual Analog Scale of Severity (VAS). Phase II of the study involved long-term (30 weeks) follow-up after completing the six week efficacy phase.ResultsAt week six post infusion, FCM, compared to placebo recipients, showed no significantly greater change-from-baseline for both primary outcome measures (IRLSS scale, FCM 500 mg vs. placebo: −8.3 ± 7.5 vs. −4.8 ± 8.7, p = 0.100; VAS, FCM 500 mg vs. placebo: −23.4 ± 24.1 vs. −13.3 ± 23.1, p = 0.077). None of the secondary outcome variables showed a significant difference at week six. Seven (21.9%) of the 32 subjects treated with iron in Phase I remained free from further RLS medications at 30 weeks. No serious adverse effects were found in this study.ConclusionsThis study did not show significant benefit from a single 500 mg FCM treatment for RLS symptoms. The two previous, well-controlled, trials of 1000 mg FCM showed significant treatment benefits which suggested that there may have been a clinically relevant total dose required to achieve a clinical response.     

Efficacy and safety of pramipexole in Japanese patients with primary restless legs syndrome: A polysomnographic randomized,double-blind,placebo-controlled study

ObjectiveTo evaluate the efficacy of pramipexole on polysomnographic measures, patient ratings and a clinical rating in Japanese patients with primary restless legs syndrome (RLS).MethodsPatients with moderate to severe RLS having periodic limb movements in bed index (PLMI) ? 5 were randomly assigned to receive pramipexole or placebo in a 6-week, double-blind, placebo-controlled study with forced titration from 0.125 to 0.75 mg/day. Both polysomnography (PSG) and the suggested immobilization test (SIT) were performed at baseline and 6 weeks after starting treatment.ResultsThe analysis of covariance of log-transformed PLMI showed that the adjusted means at the end of study were significantly smaller in the pramipexole group than in the placebo group (p = 0.0019). In all patients, variables on SIT did not show any differences between the two groups, whereas a significant improvement was shown in the pramipexole group compared with the placebo group for patients with a SIT-PLM index at baseline ? 15. Pramipexole group showed a significant reduction in the International Restless Legs Syndrome Study Group rating scale (IRLS; p = 0.0005), a significant improvement in both Patient Global Impression (PGI; p < 0.0001) and Clinical Global Impressions (CGI-I; p = 0.0488), and a significantly greater mean reduction in the Pittsburgh Sleep Quality Index (PSQI; p = 0.0016), when compared with those of placebo group at week 6.ConclusionsPramipexole is highly efficacious in the reduction of PLMI and in the improvement of subjective severity of RLS and subjective sleep disturbance caused by the disorder.