PO104 Placebo and nocebo responses in rls: a meta-analysis

Filipe B Rodrigues, Gonçalo S Duarte, Maria A Silva, Ricardo M Fernandes, Daisy Abreu, Tiago Mestre, João Costa, Claudia Trenkwalder, Joaquim J Ferreira
2017 Journal of Neurology, Neurosurgery and Psychiatry  
Objective Our goals were to estimate the placebo and nocebo responses in restless legs syndrome (RLS). Methods Databases were searched up to October 2015. Randomised, double-blind, placebo-controlled trials of RLS patient were included. 'Placebo response' was defined as the withingroup change from baseline, using any scale measuring RLS severity or disability. 'Nocebo response' was defined as the proportion of patients experiencing adverse events in the placebo arm. Random-effects meta-analysis
more » ... fects meta-analysis was used to pool data. Results We included 5046 participants. Pooled placebo response effect size was À1.41 (95%CI:À1.56-À1.25), corresponding to À6.58 points in the International RLS Study Group Scale (IRLS). Pooled nocebo response was 45.36% (95%CI:40.47%-50.29%). The placebo and nocebo responses were greater in trials with longer duration, evaluating pharmacological interventions and idiopathic RLS, and in industry funded and unpublished studies. The placebo response was considerable smaller in objective as compared to subjective outcomes. In addition, the nocebo response increases proportionally with the placebo response, and has the same predictors. Conclusions The magnitude of the placebo response in RLS is above the threshold of minimal clinical important difference, and the frequency of adverse events is also considerable. These results are relevant to inform the design and interpretation of future clinical trials. Background/Aim The density of the dopamine transporter (DAT) continues to decline in the striatum of Parkinson's disease (PD) patients, while they get at risk for developing levodopa-induced dyskinesias (LIDs). Here, we studied the role of DAT-specific imaging as a prognostic marker of dyskinesias. Methods We retrospectively selected 42 PD patients who had SPECT imaging with 123I-Ioflupane approximately five years ago during the diagnosis of PD. 15 patients of them were rescanned with 123I-Ioflupane SPECT after 6.3±3.0 years. We divided the PD patients according to the presence or absence of dyskinesias. SPECT data were analysed for the putamen by a semi-quantification approach.
doi:10.1136/jnnp-2017-abn.134 fatcat:bo5tluyxsnfbtdwst7rqjkcq4m