Mariska Leeflang

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BACKGROUND In drug development, a 4-phase hierarchical model for the clinical evaluation of new pharmaceuticals is well known. Several comparable phased evaluation schemes have been proposed for medical tests. PURPOSE To perform a systematic search of the literature, a synthesis, and a critical review of phased evaluation schemes for medical tests. DATA(More)
BACKGROUND Optimal cutoff values for tests results involving continuous variables are often derived in a data-driven way. This approach, however, may lead to overly optimistic measures of diagnostic accuracy. We evaluated the magnitude of the bias in sensitivity and specificity associated with data-driven selection of cutoff values and examined potential(More)
BACKGROUND The interest in prognostic reviews is increasing, but to properly review existing evidence an accurate search filer for finding prediction research is needed. The aim of this paper was to validate and update two previously introduced search filters for finding prediction research in Medline: the Ingui filter and the Haynes Broad filter. (More)
BACKGROUND Point-of-care (POC) tests for diagnosing schistosomiasis include tests based on circulating antigen detection and urine reagent strip tests. If they had sufficient diagnostic accuracy they could replace conventional microscopy as they provide a quicker answer and are easier to use. OBJECTIVES To summarise the diagnostic accuracy of: a) urine(More)
OBJECTIVES Development of medical test guidelines differs from intervention guideline development. These differences can pose unique challenges in building evidence-based recommendations to guide clinical practice. The aim of our study was to better understand these challenges, explore reasons behind them and identify possible solutions. SETTING AND(More)
BACKGROUND To describe approaches used in systematic reviews of diagnostic test accuracy studies for assessing variability in estimates of accuracy between studies and to provide guidance in this area. METHODS Meta-analyses of diagnostic test accuracy studies published between May and September 2012 were systematically identified. Information on how the(More)
BACKGROUND Studies on time to diagnosis are an increasing field of clinical research that may help to plan corrective actions and identify inequities in access to healthcare. Specific features of time to diagnosis studies, such as how participants were selected and how time to diagnosis was defined and measured, are poorly reported. The present study aims(More)
BACKGROUND The value of a medical test depends on the context in which it might be used. Ideally, questions, results and conclusions of a diagnostic test accuracy (DTA) systematic review should be presented in light of this context. There is increasing acceptance of the value for knowing the impact a test can have on downstream consequences such as costs,(More)
Systematic reviews are widely considered as the highest form of medical evidence , since they aim to be a repeatable, comprehensive, and unbiased summary of the existing literature. Because of the high cost of missing relevant studies, review authors go to great lengths to ensure all relevant literature is included. It is not atypical for a single review to(More)