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Predictors of time to requiring dopaminergic treatment in 2 Parkinson's disease cohorts

Authors

  • Connie Marras MD, PhD,

    Corresponding author
    1. Morton and Gloria Shulman Movement Disorders Centre, Toronto Western Hospital, Toronto, Ontario, Canada
    2. University of Toronto, Toronto, Ontario, Canada
    • Connie Marras, Toronto Western Hospital Movement Disorders Centre, 399 Bathurst Street, Toronto, ON M5T 2S8, Canada

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  • Michael P. McDermott PhD,

    1. University of Rochester, Rochester, New York, USA
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  • Ken Marek MD,

    1. Institute for Neurodegenerative Disorders, New Haven, Connecticut, USA
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  • Paula Rochon MD, MPH,

    1. University of Toronto, Toronto, Ontario, Canada
    2. Women's College Research Institute, Women's College Hospital, Toronto, Ontario, Canada
    3. Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada
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  • Gary Naglie MD,

    1. University of Toronto, Toronto, Ontario, Canada
    2. Toronto Rehabilitation Institute, Toronto, Ontario Canada
    3. Division of Clinical Decision Making and Health Care, Toronto General Research Institute, Toronto, Ontario, Canada
    4. University Health Network, Divisions of General Internal Medicine and Geriatrics Program, Toronto, Ontario, Canada
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  • Caroline M. Tanner MD, PhD,

    1. The Parkinson's Institute, Sunnyvale, California, USA
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  • Alice Rudolph PhD,

    1. University of Rochester, Rochester, New York, USA
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  • Ira Shoulson MD,

    1. University of Rochester, Rochester, New York, USA
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  • Anthony E. Lang MD,

    1. Morton and Gloria Shulman Movement Disorders Centre, Toronto Western Hospital, Toronto, Ontario, Canada
    2. University of Toronto, Toronto, Ontario, Canada
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  • on behalf of the Parkinson Study Group DATATOP and PRECEPT investigators

    1. Morton and Gloria Shulman Movement Disorders Centre, Toronto Western Hospital, Toronto, Ontario, Canada
    2. University of Toronto, Toronto, Ontario, Canada
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  • Relevant conflict of interest: Nothing to report.

Abstract

The rate of progression of Parkinson's disease (PD) is highly variable. Knowledge of factors associated with disease milestones and commonly used research outcome measures helps with patient counseling and guides the design and interpretation of clinical studies. The objective of the study was to identify prognostic factors for time to acquiring disability requiring dopaminergic therapy that are reproducible within 2 large prospectively followed cohorts. Potential prognostic factors were identified using data from the Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism (DATATOP) trial, and their reproducibility was examined using data from the Parkinson Research Examination of CEP-1347 trial (PRECEPT). In multivariable analyses of the DATATOP cohort, higher baseline Unified Parkinson's Disease Rating Scale (UPDRS) scores, full-time employment, a lesser smoking history, and onset on the left side were associated with a shorter time to disability requiring dopaminergic therapy. PRECEPT data confirmed the associations of higher baseline UPDRS scores and full-time employment with shorter time to requiring treatment. Any clinical trial using the end point of time to disability requiring dopaminergic therapy should ensure that groups are well balanced with respect to baseline UPDRS scores and the proportion of subjects employed full time and should consider including these variables as covariates in the statistical model for primary analysis of treatment effects. We suspect that individuals employed full time may have a lower threshold for requiring dopaminergic therapy because of occupational demands. © 2011 Movement Disorder Society

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