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Sample sizes for brain atrophy outcomes in trials for secondary progressive multiple sclerosis

Altmann, D. R. and Jasperse, B. and Barkhof, F. and Beckmann, K. and Filippi, M. and Kappos, L. D. and Molyneux, P. and Polman, C. H. and Pozzilli, C. and Thompson, A. J. and Wagner, K. and Yousry, T. A. and Miller, D. H.. (2009) Sample sizes for brain atrophy outcomes in trials for secondary progressive multiple sclerosis. Neurology : journal of the American Academy of Neurology, Vol. 72. pp. 595-601.

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Official URL: http://edoc.unibas.ch/dok/A6005631

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Abstract

BACKGROUND: Progressive brain atrophy in multiple sclerosis (MS) may reflect neuroaxonal and myelin loss and MRI measures of brain tissue loss are used as outcome measures in MS treatment trials. This study investigated sample sizes required to demonstrate reduction of brain atrophy using three outcome measures in a parallel group, placebo-controlled trial for secondary progressive MS (SPMS). METHODS: Data were taken from a cohort of 43 patients with SPMS who had been followed up with 6-monthly T1-weighted MRI for up to 3 years within the placebo arm of a therapeutic trial. Central cerebral volumes (CCVs) were measured using a semiautomated segmentation approach, and brain volume normalized for skull size (NBV) was measured using automated segmentation (SIENAX). Change in CCV and NBV was measured by subtraction of baseline from serial CCV and SIENAX images; in addition, percentage brain volume change relative to baseline was measured directly using a registration-based method (SIENA). Sample sizes for given treatment effects and power were calculated for standard analyses using parameters estimated from the sample. RESULTS: For a 2-year trial duration, minimum sample sizes per arm required to detect a 50% treatment effect at 80% power were 32 for SIENA, 69 for CCV, and 273 for SIENAX. Two-year minimum sample sizes were smaller than 1-year by 71% for SIENAX, 55% for CCV, and 44% for SIENA. CONCLUSION: SIENA and central cerebral volume are feasible outcome measures for inclusion in placebo-controlled trials in secondary progressive multiple sclerosis.
Faculties and Departments:03 Faculty of Medicine > Bereich Medizinische Fächer (Klinik) > Neurologie > Neuroimmunologie (Kappos)
03 Faculty of Medicine > Departement Klinische Forschung > Bereich Medizinische Fächer (Klinik) > Neurologie > Neuroimmunologie (Kappos)
UniBasel Contributors:Kappos, Ludwig
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:Lancet Publications
ISSN:0028-3878
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:01 Mar 2013 11:14
Deposited On:01 Mar 2013 11:11

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