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Validation of a prognostic index for Huntington's disease
Journal article   Open access   Peer reviewed

Validation of a prognostic index for Huntington's disease

Jeffrey D Long, Douglas R Langbehn, Sarah J Tabrizi, Bernhard G Landwehrmeyer, Jane S Paulsen, John Warner and Cristina Sampaio
Movement disorders, Vol.32(2), pp.256-263
02/2017
DOI: 10.1002/mds.26838
PMCID: PMC5318276
PMID: 27892614
url
http://doi.org/10.1002/mds.26838View
Open Access

Abstract

Characterizing progression in Huntington's disease is important for study the natural course and selecting appropriate participants for clinical trials.\nThe aim was to develop a prognostic index for motor diagnosis in Huntington's disease and examine its predictive performance in external observational studies.\nThe prediagnosis Neuro-biological Predictors of Huntington's Disease study (N = 945 gene-positive) was used to select a Cox regression model for computing a prognostic index. Cross-validation was used for selecting a model with good internal validity performance using the research sites as natural splits of the data set. Then, the external predictive performance was assessed using prediagnosis data from three additional observational studies, The Cooperative Huntington Observational Research Trial (N = 358), TRACK-HD (N = 118), and REGISTRY (N = 480).\nModel selection yielded a prognostic index computed as the weighted combination of the UHDRS total motor score, Symbol Digit Modalities Test, baseline age, and cytosine-adenine-guanine expansion. External predictive performance was very good for the first two of the three studies, with the third being a much more progressed cohort than the other studies. The databases were pooled and a final Cox regression model was estimated. The regression coefficients were scaled to produce the prognostic index for Huntington's disease, and a normed version, which is scaled relative to a 10-year 50% probability of motor diagnosis.\nThe positive results of this comprehensive validity analysis provide evidence that the prognostic index is generally useful for predicting Huntington's disease progression in terms of risk of future motor diagnosis. The variables for the index are routinely collected in ongoing observational studies and the index can be used to identify cohorts for clinical trial recruitment. © 2016 International Parkinson and Movement Disorder Society.
Severity of Illness Index Reproducibility of Results Prognosis Humans Middle Aged Huntington Disease - genetics Adult Female Huntington Disease - diagnosis Male Longitudinal Studies Disease Progression

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