Case ascertainment uncertainties in prevalence surveys of Parkinson's disease

Authors

  • Dr. Dallas W. Anderson PhD,

    Corresponding author
    1. Biometry and Field Studies Branch, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, U.S.A.
    • Anderson at the National Institutes of Health, National Institute of Neurological Disorders and Stroke, Federal Building, Room 7C-16, Bethesda, MD 20892–9135, U.S.A.
    Search for more papers by this author
  • Walter A. Rocca MD, MPH,

    1. Departments of Health Sciences Research, Rochester, Minnesota, U.S.A.
    2. Neurology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota, U.S.A.
    Search for more papers by this author
  • Maarten C. De Rijk MD, PhD,

    1. Department of Epidemiology and Biostistics, Erasmus University Medical School, Rotterdam, the Netherlands
    2. Department of Neurology and Erasmus Center for Research on Aging, Erasmus University Medical School, Rotterdam, the Netherlands
    Search for more papers by this author
  • Francesco Grigoletto ScD,

    1. Institute of Hygiene, University of Padua, Padua, Italy
    Search for more papers by this author
  • Mario O. Melcon MD,

    1. Department of Neurology, Regional Hospital, Junín, Buenos Aires Province, Arentina
    Search for more papers by this author
  • Monique M. B. Breteler MD, PhD,

    1. Department of Epidemiology and Biostistics, Erasmus University Medical School, Rotterdam, the Netherlands
    Search for more papers by this author
  • Demetrius M. Maraganore MD

    1. Neurology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota, U.S.A.
    Search for more papers by this author

Abstract

Using unpublished data from five completed prevalence surveys of Parkinson's disease (PD), we investigated case ascertainment uncertainties that potentially have a direct effect on prevalence. These uncertainties arise from the choice of diagnostic criteria, the choice of screening method, and the amount of information lost because of nonresponse. The surveys were conducted in Argentina, India, China, Italy, and the Netherlands. Our analyses consisted of simple comparisons of prevalence results, positive predictive values (a screening measure), and nonresponse percentages. We found that (a) prevalence comparisons between surveys have diminished value if the surveys used different diagnostic criteria for PD; (b) screening performance may be affected adversely if symptom questions are answered by one family member for the entire family living together rather than by each family member individually; and (c) nonresponse from refusal or unavailability does not necessarily lead to bias, but special caution may be appropriate with prevalence results pertaining to elderly women.

Ancillary