Detecting treatment effects on brain atrophy in relapsing remitting multiple sclerosis: sample size estimates

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Show simple item record Anderson, Valerie en Bartlett, JW en Fox, NC en Fisniku, L en Miller, DH en
dc.coverage.spatial Germany en 2012-02-23T01:08:47Z en 2007-11 en
dc.identifier.citation Journal of Neurology 254(11):1588-1594 Nov 2007 en
dc.identifier.issn 0340-5354 en
dc.identifier.uri en
dc.description.abstract Brain atrophy, thought to reflect neuroaxonal degeneration, may be considered an objective marker of disease progression in multiple sclerosis (MS). Our objective was to estimate sample sizes required for parallel group placebo-controlled trials of disease-modifying treatments in relapsing remitting MS (RRMS), using brain atrophy on MRI as the outcome measure. In addition, we investigated how brain atrophy measurement method and trial duration affect sample sizes. Thirty-three patients with RRMS and 16 controls had T1-weighted volumetric MR imaging acquired at baseline and up to six repeat time-points (six monthly intervals). Brain atrophy was quantified between baseline and each repeat image using four methods: segmented brain volume difference, BBSI, SIENA and ventricular enlargement. Linear mixed models were fitted to data from each subject group and method. Sample size calculations were performed using mean and variance estimates from these models. For a 2 year trial, a treatment slowing atrophy rate by 30% required 123 subjects in each treatment arm if using SIENA to measure atrophy, 157 for the BBSI, 140 for ventricular enlargement and 763 for segmented brain volume difference. For a given effect size and method, sample sizes were statistically significantly reduced the longer the trial duration. Our estimations suggest that brain atrophy could provide an additional outcome measure to clinical assessment for monitoring treatment effects in RRMS although the relationship between atrophy and subsequent disability, and potential confounding factors to atrophy measurement must be further investigated. en
dc.language eng en
dc.publisher Springer Medizin en
dc.relation.ispartofseries Journal of Neurology en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from en
dc.rights.uri en
dc.subject Adult en
dc.subject Atrophy en
dc.subject Brain en
dc.subject Cerebral Ventricles en
dc.subject Cohort Studies en
dc.subject Disease Progression en
dc.subject Female en
dc.subject Humans en
dc.subject Image Processing, Computer-Assisted en
dc.subject Linear Models en
dc.subject Magnetic Resonance Imaging en
dc.subject Male en
dc.subject Multiple Sclerosis, Relapsing-Remitting en
dc.subject Outcome Assessment (Health Care) en
dc.subject Severity of Illness Index en
dc.subject Time Factors en
dc.title Detecting treatment effects on brain atrophy in relapsing remitting multiple sclerosis: sample size estimates en
dc.type Journal Article en
dc.identifier.doi 10.1007/s00415-007-0599-3 en
pubs.issue 11 en
pubs.begin-page 1588 en
pubs.volume 254 en
dc.rights.holder Copyright: Springer Medizin en
dc.identifier.pmid 17940723 en
pubs.end-page 1594 en
dc.rights.accessrights en
pubs.subtype Article en
pubs.elements-id 163802 en
pubs.record-created-at-source-date 2012-01-25 en
pubs.dimensions-id 17940723 en

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