Efficacy of gabapentin enacarbil in adult patients with severe primary restless legs syndrome

AimAssess efficacy and tolerability of gabapentin enacarbil (GEn) in adults with severe primary restless legs syndrome (RLS).MethodsWe pooled data from three 12-week, double-blind, placebo-controlled, randomized trials (NCT00298623, NCT00365352, NCT01332305) across GEn 600-mg, GEn 1200-mg, and placebo treatment groups for severe primary RLS (baseline International Restless Legs Scale (IRLS) total score ≥24). Co-primary end points at week 12 were mean change from baseline in IRLS total score and proportion of responders (“much”/very much” improved) on the investigator-rated Clinical Global Impression – Improvement (CGI-I) Scale. Outcomes for individual IRLS items (eg, sleep, mood, quality of life, pain, safety) were assessed.ResultsA total of 309 patients had severe primary RLS (placebo, n = 110; GEn 600 mg, n = 80; GEn 1200 mg, n = 119). GEn 600 mg and 1200 mg significantly improved least-squares mean IRLS total scores versus placebo at week 12 (placebo, −12.3; GEn 600 mg, −16.3; GEn 1200 mg, −18.0; treatment difference vs. placebo, both p <0.01). Significantly more patients with severe primary RLS treated with GEn 600 mg (64%) and 1200 mg (74%) were CGI-I responders at week 12 versus placebo (42%; p <0.01 for both GEn doses). Both GEn doses led to significant improvements in the other outcomes explored versus placebo at week 12. The most frequent treatment-emergent adverse events (TEAEs) were somnolence (GEn, 21–24%; placebo, 3%) and dizziness (GEn, 14–19%; placebo, 3%).ConclusionsGEn (600 mg or 1200 mg) once daily significantly improved RLS symptoms and consequences of these symptoms in severe primary RLS. The most frequent TEAEs were somnolence and dizziness.     

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.     

Ropinirole is effective in the treatment of restless legs syndrome. TREAT RLS 2: a 12-week, double-blind, randomized, parallel-group, placebo-controlled study.

Restless legs syndrome (RLS) is a neurological condition with significant impact on sleep and quality of life (QoL). This double-blind, randomized, 12-week, multinational study compared the efficacy and safety of ropinirole and placebo in RLS. In total, 267 outpatients with moderate-to-severe RLS were randomly assigned to ropinirole (0.25-4.0 mg/day) or placebo, 1 to 3 hours before bedtime. The primary endpoint was the change in International Restless Legs Scale (IRLS) score at week 12. Key secondary endpoints were the percentage of patients showing significant improvement on the Clinical Global Impression-Improvement (CGI-I) scale at week 12 and changes in IRLS and CGI-I scale scores at week 1. Other measures included the Medical Outcomes Study sleep scale and Restless Legs Syndrome Quality of Life questionnaire. Improvements were significantly greater for ropinirole than placebo for change in IRLS score at week 12 (-11.2 [SE 0.76] vs. -8.7 [0.75], respectively; adjusted treatment difference -2.5 [95% confidence interval [CI], -4.6, -0.4], P = 0.0197); all key secondary endpoints; sleep and QoL parameters. Adverse events were typical for dopamine agonists; disease augmentation, although not directly assessed, was not reported during treatment. Ropinirole improves symptoms, associated sleep disturbance, and QoL of RLS patients and is generally well tolerated.     

Long-term efficacy and safety of gabapentin enacarbil in Japanese restless legs syndrome patients

Several short- and long-term studies conducted in Europe/North America have demonstrated good efficacy and tolerability of 600-1800 mg gabapentin enacarbil (GEn). However, no studies have evaluated the efficacy of long-term treatment with GEn in Asian patients. Therefore, the objective of this study was to evaluate the efficacy and safety of long-term treatment with GEn in Japanese patients with restless legs syndrome (RLS) in a multicenter open-label study. RLS patients aged 20-80 years were allocated to receive oral GEn 1200 mg/day for a treatment period of 52 weeks. International Restless Legs Syndrome Scale (IRLS) score, investigator- and patient-rated Clinical Global Impression (CGI) scores, Pittsburgh Sleep Quality Index (PSQI) total scores and subscores, and short form (SF)-36 subscores were assessed, and adverse events (AEs) were monitored. In 181 patients (mean age, 54.9±12.2 years; BMI, 23.0±2.6 kg/m2) IRLS score decreased from 24.4±0.4 at baseline to 6.3±0.6 at week 52, with a reduction of -18.0±0.6. The IRLS responder rate was 80.3% at week 52. ICGI and PCGI responder rates were 87.1% and 87.1%, respectively. PSQI and SF-36 also showed significant improvements. AEs were reported in 96.2% of patients but remained mild-to-moderate in nearly all the cases. Serious AEs occurred in 1.6%. Dizziness and somnolence were noted in 46.2% and 41.2% of patients, respectively, and mostly occurred during the first 4 weeks. No episodes of augmentation were reported. In conclusion, long-term treatment with GEn improved RLS symptoms as well as investigator- and patient-reported outcomes in Japanese patients with moderate-to-severe RLS, with an acceptable safety profile. Randomized, double-blind, placebo/active-controlled trials are desirable to confirm these preliminary results.     

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.     

Ropinirole is effective in the long-term management of restless legs syndrome: a randomized controlled trial.

The objective of this study was to investigate the long-term efficacy of ropinirole in patients with restless legs syndrome (RLS) and to assess the potential for relapse after the discontinuation of active treatment. Patients with primary RLS (n = 202) received single-blind ropinirole for 24 weeks. Patients meeting treatment continuation criteria were randomized to double-blind treatment with ropinirole or placebo for a further 12 weeks. The primary efficacy variable was the proportion of patients relapsing during double-blind treatment. Additional efficacy measures included time to relapse, withdrawals due to lack of efficacy, improvement on the Clinical Global Impression-Improvement (CGI-I) scale, change in International Restless Legs Scale (IRLS) score during double-blind treatment, and changes in sleep and quality of life (QoL) parameters. Significantly fewer patients relapsed on ropinirole than on placebo (32.6% vs. 57.8%; P = 0.0156). Time to relapse was longer with ropinirole and more patients withdrew due to lack of efficacy with placebo. Patients showed improvements in IRLS and CGI-I scores, sleep and QoL parameters with single-blind ropinirole, which were better maintained when ropinirole was continued during the double-blind phase, but reduced with placebo. Ropinirole was well tolerated; adverse events were typical for dopamine agonists. Ropinirole was highly effective and well tolerated in the long-term management of RLS, with pharmacological effect over 36 weeks.     

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.     

Correlation between rating scales and sleep laboratory measurements in restless legs syndrome

OBJECTIVES: The aim of this study was to test the external validity of the International Restless Legs Scale (IRLS) by assessment of the correlation between IRLS scores and objective measures of severity such as polysomnography (PSG) and Suggested Immobilization Test (SIT). DESIGNS: Correlation analysis between rating scales for RLS (IRLS and Johns Hopkins RLS Scale--JHRLSS) and sleep laboratory measurements in untreated RLS patients. METHODS: The study included 30 untreated patients diagnosed with RLS according to the criteria of the International RLS Study Group. Diagnostic procedures included physical exam, laboratory analysis, PSG and a nocturnal SIT. Statistical analysis was performed by means of Spearman's correlations and Kruskal-Wallis test. RESULTS: IRLS correlated significantly with Periodic Leg Movement of Sleep-index (PLMS), and PLMS-arousal index during PSG as well as with Periodic Leg Movement of Wakefulness (PLMW) during SIT (SIT-PLMW) (all r=0.4; p<0.01). There was no correlation between IRLS and the number of PLMW in PSG (PSG-PLMW) or any other sleep variable during PSG. Nor was any correlation found between IRLS scores and ferritin, age, duration of illness or any other clinical variables. CONCLUSIONS: This study represents the first demonstration of a correlation between IRLS and objective parameters of motor dysfunction such as PLMS-index or SIT. This finding is particularly relevant for the design of future clinical trials. Furthermore, the association between PLMS and SIT-PLMW supports the view that both PLMS and PLMW might share a common mechanism.     

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.     

Gabapentin enacarbil,pregabalin and rotigotine are equally effective in restless legs syndrome: a comparative meta‐analysis

To synthesize evidence from available randomized controlled trials (RCT) to compare the efficacies of dopaminergic drugs (pramipexole, ropinirole and rotigotine) and α‐2‐δ ligands (gabapentin enacarbil and pregabalin) for the treatment of restless legs syndrome (RLS). We searched PubMed for all eligible RCTs. Network meta‐analysis using frequentist methodology with random effect models was performed for mean changes in scores on the International RLS Study Group Rating Scale (IRLS) and for responder rates on Clinical Global Impressions‐Improvement (CGI‐I); analyzed as odds ratio (OR). Network meta‐analysis of mean changes in IRLS data from 35 studies with 7333 participants showed that all treatments, in specific gabapentin enacarbil, followed by pregabalin and rotigotine were superior to placebo [mean reduction in IRLS scores: ?5.31 (?6.74 to ?3.87), ?5.20 (?6.91 to ?3.49), 5.17 (3.73–6.61), respectively] but there were no significant differences between active treatments. Network meta‐analysis of 5137 participants from 24 studies showed that gabapentin enacarbil and rotigotine were associated with the highest CGI‐I response rates [ORs: 5.68; (95% CI, 4.14–7.21); and 4.68 (2.87–6.49), compared to placebo, respectively]. No significant inter‐treatment differences exist, except for that between gabapentin enacarbil and ropinirole. Based on IRLS scores and CGI‐I response rates, while gabapentin enacarbil, pregabalin and rotigotine stand out as the most efficacious of all examined drugs, it is noteworthy that no significant inter‐treatment differences exist, except for that between gabapentin enacarbil and ropiniriole (for CGI‐I response rates).     

Noninvasive Vagus Nerve Stimulation: A New Therapeutic Approach for Pharmacoresistant Restless Legs Syndrome

AimsThis work aimed to study the effect of noninvasive vagus nerve stimulation on severe restless legs syndrome (RLS) resistant to pharmacotherapy.Materials and MethodsPatients with severe pharmacoresistant RLS were recruited from a tertiary care sleep center. Intervention was one-hour weekly sessions of transauricular vagus nerve stimulation (tVNS) in the left cymba concha, for eight weeks. The primary outcome measure was the score on the International Restless Legs Rating Scale (IRLS); secondary outcome measures were quality of life (Restless Legs Syndrome Quality of Life scale [RLSQOL]), mood disorders using the Hospital Anxiety and Depression scale subscale for depression (HADD) and Hospital Anxiety and Depression scale subscale for anxiety (HADA), and objective sleep latency, sleep duration, efficiency, and leg movement time measured by actigraphy.ResultsFifteen patients, 53% male, aged mean 62.7 ± 12.3 years with severe RLS, reduced quality of life, and symptoms of anxiety and depression, were included. The IRLS improved from baseline to session eight: IRLS 31.9 ± 2.9 vs 24.6 ± 5.9 p = 0.0003. Of these participants, 27% (4/15) had a total response with a decrease below an IRLS score of 20; 40% (6/15) a partial response with an improvement in the IRLS > 5 but an IRLS above 20; and 33% (5/15) were nonresponders. After tVNS, quality of life improved (RLSQOL 49.3 ± 18.1 vs 80.0 ± 19.6 p = 0.0005), as did anxiety (HADA 8.9 ± 5.4 vs 6.2 ± 5.0 p = 0.001) and depression (HADD 5.2 ± 4.5 vs 4.0 ± 4.0 p = 0.01). No significant change was found in actigraphic outcome measures.ConclusionsIn this pilot study, tVNS improved the symptoms of RLS in 66% of participants (10/15) with severe pharmacoresistant RLS, with concomitant improvements in quality of life and mood. Randomized controlled trials evaluating therapeutic efficacy of tVNS in RLS are needed to confirm these promising findings.     

Randomized polysomnography study of gabapentin enacarbil in subjects with restless legs syndrome

We assessed the efficacy and tolerability of gabapentin enacarbil in the treatment of moderate to severe primary restless legs syndrome and associated sleep disturbance. This was a multicenter, randomized, double‐blind, placebo‐controlled, 2‐period crossover polysomnography study of gabapentin enacarbil 1200 mg or placebo taken once daily. Subjects were randomized 1:1 to a sequence of gabapentin enacarbil:placebo or placebo:gabapentin enacarbil, receiving each treatment for 4 weeks. The primary end point was the mean change from baseline at weeks 4 and 10 (4/10) last observation carried forward in wake time during sleep. The key secondary end point was the mean change from baseline at weeks 4/10 last observation carried forward in periodic limb movements associated with arousal per hour of sleep. Tolerability assessments included adverse events. One hundred thirty‐six subjects were randomized (gabapentin enacarbil:placebo, 67; placebo:gabapentin enacarbil, 69), and 114 (gabapentin enacarbil:placebo, 53; placebo:gabapentin enacarbil, 61) completed the study. Gabapentin enacarbil 1200 mg significantly reduced wake time during sleep (mean change from baseline [adjusted mean treatment difference]: ?26.0 minutes; P < .0001) and periodic limb movements associated with arousal per hour of sleep (adjusted mean treatment difference: ?3.1 periodic limb movements with arousal/hour; P = .002) compared with placebo at weeks 4/10 last observation carried forward. The most commonly reported adverse events were dizziness (gabapentin enacarbil 20%, placebo 2%) and somnolence (gabapentin enacarbil 13%, placebo 2%). Gabapentin enacarbil 1200 mg once daily significantly reduces restless legs syndrome–associated sleep disturbance and periodic limb movements associated with arousal per hour of sleep and is generally well tolerated in adults with moderate to severe primary restless legs syndrome. © 2011 Movement Disorder Society     

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.     

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.     

Rating of daytime and nighttime symptoms in RLS: validation of the RLS-6 scale of restless legs syndrome/Willis–Ekbom disease

BackgroundThe International Restless Legs Scale (IRLS) is the most widely used of the scales rating the severity of restless legs syndrome/Willis–Ekbom disease (RLS/WED). It has been well validated and is the primary end point for most of the therapeutic and nontherapeutic studies of RLS/WED. It has excellent psychometric properties, although it does not capture the severity of RLS under a wide variety of circumstances and times of day. Moreover, the IRLS has a large placebo effect.MethodsThe Restless Legs Syndrome-6 Scale (RLS-6), however, takes another potentially valuable approach. Six items are rated on a 0–10 scale from no symptoms at 0 to very severe at 10. In addition to questions on satisfaction with sleep and sleepiness, the scale rates the severity of RLS for the past week under four separate circumstances: while falling asleep, during the night, during the day while sitting or lying, and during the day when moving around. The purpose of the current study is to report the validation of the RLS-6 under baseline and therapeutic conditions.ResultsThe RLS-6 seems to be an acceptable, reliable, precise, valid, and responsive instrument for the assessment of RLS severity in a specific and pragmatic manner.ConclusionsAt present, we view the RLS-6 not as a replacement for the IRLS but as a supplement, as each scale provides information not captured by the other.     

Correlation between putative indicators of primary restless legs syndrome severity

BACKGROUND AND PURPOSE: Several methods of assessing disease severity in restless legs syndrome (RLS) have been suggested. The purpose of this study was to examine the relationship between the suggested immobilization test (SIT), the International RLS Study Group rating scale (IRLS), sleep efficiency, and periodic leg movements of sleep index (PLMI). PATIENTS AND METHODS: Forty primary RLS patients with periodic leg movements of sleep were included in this prospective study. Study procedures were all performed during the same night, beginning with IRLS administration and following with SIT and polysomnography (PSG) evaluations, in that order. SIT was composed of two parameters: SIT mean discomfort score (SIT-MDS) and SIT periodic leg movements of wakefulness index (SIT-PLMW). PSG target measures were PLMI and sleep efficiency. Pearson's correlation was used for analysis at a P<0.01 significance level. RESULTS: PSG-PLMI correlated with IRLS (r=0.462; P=0.003) and with SIT-PLMW (r=0.681; P=0.0004). A correlation was also found between IRLS and SIT-MDS (r=0.447; P=0.004), even though SIT-PLMW and IRLS did not correlate with each other (P=0.286). A negative correlation was found between PSG-PLMI and sleep efficiency (r=-0.435; P=0.005). Neither SIT nor IRLS correlated with sleep efficiency. Only SIT discomfort scores from the second half of SIT correlated with SIT-PLMW (r=0.457, P=0.004), and they had a stronger correlation with IRLS (P=0.003). CONCLUSIONS: This study attempted a much needed comprehensive evaluation of the relationship between various RLS severity indicators. Our findings support a strong role of motor dysfunction on sleep quality in RLS, as well as the potential use of SIT-PLMW as a sensitive indicator of RLS severity.     

An item response analysis of the international restless legs syndrome study group rating scale for restless legs syndrome

BACKGROUND AND PURPOSE: Restless legs syndrome (RLS) is a common central nervous system disorder; however, there is currently a lack of well-validated and easily-administered measures of RLS severity available. The International Restless Legs Syndrome Study Group has recently developed a 10-item scale to meet this need. The International Restless Legs Severity Scale (IRLS) has been shown to have a high degree of reliability, validity, and internal consistency. In order to further demonstrate the validity of the IRLS, the present study examined the relationship between scores on individual IRLS items and overall RLS severity. PATIENTS AND METHODS: The 10-item IRLS was administered to 196 RLS patients. Option characteristic curves (the probability of scoring different options for a given item as a function of overall IRLS score) were generated in order to illustrate the scoring patterns for each item across the range of total RLS severity. Item characteristic curves (the expected score on an item as a function of overall IRLS score) were also generated to illustrate the relationship between scores on the individual items and total RLS severity. RESULTS: The IRLS items demonstrated excellent item response properties, with option and item characteristic curves closely approximating those of an ideal item. Item 3 (relief of arm or leg discomfort from moving around) was the most problematic item in that a 'floor' effect was evident; however, the item response characteristics for this item were still acceptable. CONCLUSIONS: Each IRLS item showed a good relationship between responses on that item and overall RLS severity, providing further evidence for the validity of the IRLS as a measure of RLS severity in RLS patients.     

The reliability, validity and responsiveness of the International Restless Legs Syndrome Study Group rating scale and subscales in a clinical-trial setting

PATIENTS AND METHODS: To assess the reliability, validity, and responsiveness of the International Restless Legs Syndrome Study Group's rating scale (the International Restless Legs Scale (IRLS)) (V2.0), using pooled data from two matching, placebo-controlled studies of ropinirole for treating Restless Legs Syndrome (RLS). RESULTS: Pooled patient samples comprised 550 patients in the baseline (validation) sample and 439 patients in the week 12 longitudinal (responsiveness) sample. Factor analysis revealed acceptability of the IRLS total score (accounting for 40% of the variance) and that nine of the 10 IRLS items could also be assigned to two distinct subscales, the symptoms or symptoms impact subscales. The IRLS total score, symptoms and symptoms impact subscales had acceptable construct validity, internal consistency reliability (alpha=0.81, 0.80, and 0.76, respectively), and concurrent validity (r=-0.68, -0.52, -0.70, respectively, with the Restless Legs Syndrome Quality of Life questionnaire (RLSQoL) overall life impact score). IRLS scores differed significantly between different levels of sleep problems and Clinical Global Impression (CGI) of health status (P<0.0001), indicating known groups and clinical validity, respectively. Changes in scores differed significantly among CGI 'global improvement' levels (P<0.0001), providing evidence of responsiveness. CONCLUSIONS: The IRLS total score, symptoms, and symptoms impact subscales are reliable, valid, and responsive in a clinical trial setting.     

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.     

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.