Carl E Clarke

Systematic review of levodopa dose equivalency reporting in Parkinson's disease.

Interpretation of clinical trials comparing different drug regimens for Parkinsons disease (PD) is complicated by the different dose intensities used: higher doses of levodopa and, possibly, other drugs produce better symptomatic control but more late complications. To address this problem, conversion factors have been calculated for antiparkinsonian drugs that yield a total daily levodopa equivalent dose (LED). LED estimates vary, so we undertook a systematic review of studies reporting LEDs to provide standardized formulae. Electronic database and hand searching of references identified 56 primary reports of LED estimates. Data were extracted and the mean and modal LEDs calculated. This yielded a standardized LED for each drug, providing a useful tool to express dose intensity of different antiparkinsonian drug regimens on a single scale. Using these conversion formulae to report LEDs would improve the consistency of reporting and assist the interpretation of clinical trials comparing different PD medications.

Idiopathic intracranial hypertension

Idiopathic intracranial hypertension is common in obese women and can lead to significant visual impairment. First described more than 100 years ago, the cause of the disorder remains unknown. Despite a multitude of proposed links, the aetiology has never been established. Impairment of cerebrospinal-fluid reabsorption is the most likely underlying pathophysiological cause of the raised pressure, but this notion has yet to be proven. Cerebral venous sinus abnormalities associated with the disorder need further exploration. Although the major symptoms of headache and visual disturbance are well documented, most data for disease outcome have been from small retrospective case series. No randomised controlled trials of treatment have been done and the management is controversial. The importance of weight loss needs clarification, the role of diuretics is uncertain, and which surgical intervention is the most effective and safe is unknown. Prospective trials to examine these issues are urgently needed.

Rotigotine Transdermal Patch in Early Parkinson's Disease : A Randomized, Double-Blind, Controlled Study Versus Placebo and Ropinirole

Rotigotine is a new, non‐ergot dopamine agonist formulated in a transdermal delivery system. The present study was to investigate the efficacy and safety of the rotigotine transdermal patch in the treatment of early Parkinsons disease. Patients (n = 561) were randomized to rotigotine, ropinirole, or placebo. The titration period was up to 13 weeks, and there was a minimum dose‐maintenance period of 24 weeks for ropinirole and 33 weeks for rotigotine. The primary endpoint was the proportion of patients with a minimum of 20% decrease in the combined Unified Parkinsons Disease Rating Scale Part II and Part III scores. The responder rate in the rotigotine group was significantly higher than in the placebo group (52% vs. 30%, P < 0.0001). Transdermal rotigotine at doses ≤8 mg/24 h did not show noninferiority to ropinirole at doses ≤24 mg/day. In a post‐hoc subgroup analysis, rotigotine ≤8 mg/24 hours had a similar efficacy to ropinirole at doses ≤12 mg/day. The rotigotine transdermal patch was well tolerated. The most common adverse events were application‐site reactions, nausea, and somnolence. Application‐site reactions were predominantly mild or moderate in intensity. In conclusion, the rotigotine transdermal patch represents an effective and safe option for the treatment of patients with early Parkinsons disease.

Physiotherapy intervention in Parkinson’s disease: systematic review and meta-analysis

Objective To assess the effectiveness of physiotherapy compared with no intervention in patients with Parkinson’s disease. Design Systematic review and meta-analysis of randomised controlled trials. Data sources Literature databases, trial registries, journals, abstract books, and conference proceedings, and reference lists, searched up to the end of January 2012. Review methods Randomised controlled trials comparing physiotherapy with no intervention in patients with Parkinson’s disease were eligible. Two authors independently abstracted data from each trial. Standard meta-analysis methods were used to assess the effectiveness of physiotherapy compared with no intervention. Tests for heterogeneity were used to assess for differences in treatment effect across different physiotherapy interventions used. Outcome measures were gait, functional mobility and balance, falls, clinician rated impairment and disability measures, patient rated quality of life, adverse events, compliance, and economic analysis outcomes. Results 39 trials of 1827 participants met the inclusion criteria, of which 29 trials provided data for the meta-analyses. Significant benefit from physiotherapy was reported for nine of 18 outcomes assessed. Outcomes which may be clinically significant were speed (0.04 m/s, 95% confidence interval 0.02 to 0.06, P<0.001), Berg balance scale (3.71 points, 2.30 to 5.11, P<0.001), and scores on the unified Parkinson’s disease rating scale (total score −6.15 points, −8.57 to −3.73, P<0.001; activities of daily living subscore −1.36, −2.41 to −0.30, P=0.01; motor subscore −5.01, −6.30 to −3.72, P<0.001). Indirect comparisons of the different physiotherapy interventions found no evidence that the treatment effect differed across the interventions for any outcomes assessed, apart from motor subscores on the unified Parkinson’s disease rating scale (in which one trial was found to be the cause of the heterogeneity). Conclusions Physiotherapy has short term benefits in Parkinson’s disease. A wide range of physiotherapy techniques are currently used to treat Parkinson’s disease, with little difference in treatment effects. Large, well designed, randomised controlled trials with improved methodology and reporting are needed to assess the efficacy and cost effectiveness of physiotherapy for treating Parkinson’s disease in the longer term.

Development of dyskinesias in a 5-year trial of ropinirole and L-dopa.

A 5‐year trial of ropinirole and levodopa in early Parkinsons disease showed that ropinirole is associated with reduced incidence of dyskinesias. This post hoc analysis investigated whether the dyskinesia‐sparing benefit of ropinirole is lost when levodopa is added to the regimen and evaluated other risk factors for developing dyskinesias. Patients receiving levodopa had a significantly higher risk of dyskinesias than those taking ropinirole monotherapy (hazard ratio [HR], 6.67; 95% confidence interval [CI], 3.23–14.29; P < 0.001). When patients randomized to ropinirole were treated with supplementary levodopa, the development of dyskinesias was not significantly different from that in those receiving levodopa from the start (HR, 0.80; 95% CI, 0.48–1.33; P = 0.39). However, the onset of dyskinesias was delayed by around 3 years compared with levodopa monotherapy. Adjusted analyses taking into account baseline and on‐treatment factors that influenced use of supplementary levodopa or the development of dyskinesias produced similar results. In conclusion, the risk of developing dyskinesias during maintained initial ropinirole monotherapy is very low. Only once levodopa is added does the risk substantially change. Early use of ropinirole postpones the onset of dyskinesias, but these benefits decline when levodopa therapy is started, with no evidence of a subsequent rapid “catch‐up” or a persisting preventive effect.

Low energy diet and intracranial pressure in women with idiopathic intracranial hypertension: prospective cohort study

Objective To observe intracranial pressure in women with idiopathic intracranial hypertension who follow a low energy diet. Design Prospective cohort study. Setting Outpatient department and the clinical research facility based at two separate hospitals within the United Kingdom. Participants 25 women with body mass index (BMI) >25, with active (papilloedema and intracranial pressure >25 cm H2O), chronic (over three months) idiopathic intracranial hypertension. Women who had undergone surgery to treat idiopathic intracranial hypertension were excluded. Intervention Stage 1: no new intervention; stage 2: nutritionally complete low energy (calorie) diet (1777 kJ/day (425 kcal/day)); stage 3: follow-up period after the diet. Each stage lasted three months. Main outcome measure The primary outcome was reduction in intracranial pressure after the diet. Secondary measures included score on headache impact test-6, papilloedema (as measured by ultrasonography of the elevation of the optic disc and diameter of the nerve sheath, together with thickness of the peripapillary retina measured by optical coherence tomography), mean deviation of Humphrey visual field, LogMAR visual acuity, and symptoms. Outcome measures were assessed at baseline and three, six, and nine months. Lumbar puncture, to quantify intracranial pressure, was measured at baseline and three and six months. Results All variables remained stable over stage 1. During stage 2, there were significant reductions in weight (mean 15.7 (SD 8.0) kg, P<0.001), intracranial pressure (mean 8.0 (SD 4.2) cm H2O, P<0.001), score on headache impact test (7.6 (SD 10.1), P=0.004), and papilloedema (optic disc elevation (mean 0.15 (SD 0.23) mm, P=0.002), diameter of the nerve sheath (mean 0.7 (SD 0.8) mm, P=0.004), and thickness of the peripapillary retina (mean 25.7 (SD 36.1) µ, P=0.001)). Mean deviation of the Humphrey visual field remained stable, and in only five patients, the LogMAR visual acuity improved by one line. Fewer women reported symptoms including tinnitus, diplopia, and obscurations (10 v 4, P=0.004; 7 v 0, P=0.008; and 4 v 0, P=0.025, respectively). Re-evaluation at three months after the diet showed no significant change in weight (0.21 (SD 6.8) kg), and all outcome measures were maintained. Conclusion Women with idiopathic intracranial hypertension who followed a low energy diet for three months had significantly reduced intracranial pressure compared with pressure measured in the three months before the diet, as well as improved symptoms and reduced papilloedema. These reductions persisted for three months after they stopped the diet.

Systematic review of paramedical therapies for Parkinson's disease

We evaluated the efficacy of physiotherapy, occupational therapy, and speech and language therapy in Parkinsons disease by synthesizing six Cochrane systematic reviews. All randomised, controlled trials examining the efficacy of a paramedical therapy versus control intervention and all those comparing the efficacy of two forms of active therapy in Parkinsons disease were included. Trials were identified by searching biomedical databases, reference lists, hand searching, and contacting investigators. The main outcome measures were quality of life, speech intelligibility, activities of daily living, and individual measures of motor and speech impairment. We identified 16 physiotherapy randomised controlled trials (399 patients), two occupational therapy trials (84 patients), and five speech and language therapy for dysarthria trials (154 patients). None of these studies examined nonpharmacological swallowing therapy for dysphagia. We were unable to perform meta‐analysis of the results because the trials used heterogeneous therapy methods and outcome measures. The trials also had marked methodological flaws that could have introduced bias. In summary, we failed to find conclusive evidence of benefit for any form of paramedical therapy sufficient to recommend them in routine clinical practice. However, this lack of evidence is not proof of a lack of effect. Further large pragmatic randomised controlled trials are required to determine the effectiveness of paramedical therapies in Parkinsons disease.

Monoamine oxidase type B inhibitors in early Parkinson's disease: meta-analysis of 17 randomised trials involving 3525 patients

Abstract Objective To quantify more reliably the benefits and risks of monoamine oxidase type B inhibitors (MAOBIs) in early Parkinsons disease. Data sources Searches of the Cochrane Library, Medline, Embase, PubMed, and Web of Science for years 1966-2003, plus major journals in the field, abstract books, and proceedings of meetings, for randomised trials comparing MAOBIs with placebo or levodopa. Data extraction Available data on mortality, motor complications, side effects, treatment compliance, and clinician rated disability (for example, unified Parkinsons disease rating scale) were extracted from 17 trials and combined using standard meta-analytic methods. Results No significant difference in mortality existed between patients on MAOBIs and control patients (odds ratio 1.13, 95% confidence interval 0.94 to 1.34; P = 0.2). Patients randomised to MAOBIs had significantly better total scores, motor scores, and activities of daily living scores on the unified Parkinsons disease rating scale at three months compared with patients taking placebo; they were also less likely to need additional levodopa (0.57, 0.48 to 0.67; P < 0.00001) or to develop motor fluctuations (0.75, 0.59 to 0.95; P = 0.02). No difference existed between the two groups in the incidence of side effects or withdrawal of patients. Conclusions MAOBIs reduce disability, the need for levodopa, and the incidence of motor fluctuations, without substantial side effects or increased mortality. However, because few trials have compared MAOBIs with other antiparkinsonian drugs, uncertainty remains about the relative benefits and risks of MAOBIs. Further large, long term comparative trials that include patient rated quality of life measures are needed.

Dopamine agonist monotherapy in Parkinson's disease.

CONTEXT Levodopa is the gold-standard therapy for Parkinsons disease. However, long-term treatment leads to involuntary movements and response fluctuations which add to the complexities of later disease-management. In addition, preclinical evidence suggests that levodopa is toxic to dopaminergic neurons. These problems have led to a move away from levodopa towards initial monotherapy with a dopamine agonist. STARTING POINT Positron-emission tomography (PET) and single-photon emission computed tomography (SPECT) tracers have been developed which may be considered surrogate markers for remaining dopaminergic neurons. In a randomised controlled trial in patients with early Parkinsons disease, the Parkinson Study Group used 123I-beta-CIT SPECT (JAMA 2002; 287: 1653-61). Those patients given pramipexole had significantly reduced loss of striatal uptake at 46 months compared with those given levodopa (16.0% vs 25.5%). In a similar trial, Alan Whone and colleagues used 18F-DOPA PET (Neurology 2002; 58 [suppl 3]: A82-83). Patients given ropinirole had significantly reduced loss of striatal uptake at 24 months compared with those given levodopa (13% vs 20%). These studies suggest that agonist monotherapy may be neuroprotective and/or that levodopa is toxic. This work has been criticised as the SPECT results may have resulted from a differential effect of the agonist and levodopa on the regulation of the dopamine transporter, thereby influencing the imaging outcome measure. Other criticisms include insufficient data on the use of the potential neuroprotectant selegiline and patients on pramipexole in the SPECT study appear to have been clinically slow progressors. Single clinical trials with each of the four modern agonists compared with levodopa show that as monotherapy the agonists delay the onset of involuntary movements, although at the expense of poorer treatment of motor impairments and disability and more dopaminergic adverse events. The only health-related quality of life data show no difference between pramipexole and levodopa after 4 years. No information on health-economics measures is available but agonists cost two to three times as much as levodopa. WHERE NEXT? Young patients should be treated with agonist monotherapy since the trials included predominantly younger patients who have a higher incidence of motor complications. Those with significant co-morbidity, dementia, or a short life-expectancy should be treated with the lowest dose of levodopa required to maintain motor function. For the vast majority though, no clear guidance can be given. Further large-scale pragmatic trials in large numbers of patients over prolonged periods are urgently required.

Large-scale replication and heterogeneity in Parkinson disease genetic loci

Objective: Eleven genetic loci have reached genome-wide significance in a recent meta-analysis of genome-wide association studies in Parkinson disease (PD) based on populations of Caucasian descent. The extent to which these genetic effects are consistent across different populations is unknown. Methods: Investigators from the Genetic Epidemiology of Parkinsons Disease Consortium were invited to participate in the study. A total of 11 SNPs were genotyped in 8,750 cases and 8,955 controls. Fixed as well as random effects models were used to provide the summary risk estimates for these variants. We evaluated between-study heterogeneity and heterogeneity between populations of different ancestry. Results: In the overall analysis, single nucleotide polymorphisms (SNPs) in 9 loci showed significant associations with protective per-allele odds ratios of 0.78–0.87 (LAMP3, BST1, and MAPT) and susceptibility per-allele odds ratios of 1.14–1.43 (STK39, GAK, SNCA, LRRK2, SYT11, and HIP1R). For 5 of the 9 replicated SNPs there was nominally significant between-site heterogeneity in the effect sizes (I2 estimates ranged from 39% to 48%). Subgroup analysis by ethnicity showed significantly stronger effects for the BST1 (rs11724635) in Asian vs Caucasian populations and similar effects for SNCA, LRRK2, LAMP3, HIP1R, and STK39 in Asian and Caucasian populations, while MAPT rs2942168 and SYT11 rs34372695 were monomorphic in the Asian population, highlighting the role of population-specific heterogeneity in PD. Conclusion: Our study allows insight to understand the distribution of newly identified genetic factors contributing to PD and shows that large-scale evaluation in diverse populations is important to understand the role of population-specific heterogeneity. Neurology® 2012;79:659–667