• Evaluation of a questionnaire to assess selected infectious diseases and their risk factors : findings of a multicenter study.

      Sievers, Claudia; Akmatov, Manas K; Kreienbrock, Lothar; Hille, Katja; Ahrens, Wolfgang; Günther, Kathrin; Flesch-Janys, Dieter; Obi, Nadia; Michels, Karin B; Fricke, Julia; et al. (2014-11)
      The risk to die from an infectious disease in Germany has been continuously decreasing over the last century. Since infections are, however, not only causes of death but risk factors for diseases like cardiovascular diseases, it is essential to monitor and analyze their prevalence and frequency, especially in consideration of the increased life expectancy. To gain more knowledge about infectious diseases as risk factors and their implications on the condition and change of the immune status, the German National Cohort (GNC), a population-based prospective cohort study, will recruit 200,000 subjects between 2014 and 2017. In Pretest 1, a feasibility study for the GNC, we evaluated a self-administered and self-report questionnaire on infectious diseases and on the use of health care facilities (hereinafter called "ID Screen") for feasibility and validity.
    • Partial verification bias and incorporation bias affected accuracy estimates of diagnostic studies for biomarkers that were part of an existing composite gold standard.

      Karch, Annika; Koch, Armin; Zapf, Antonia; Zerr, Inga; Karch, André; Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany. (2016-10)
      To investigate how choice of gold standard biases estimates of sensitivity and specificity in studies reassessing the diagnostic accuracy of biomarkers that are already part of a lifetime composite gold standard (CGS).