Careful thought must be put into selecting the prognostic factors that we are interested in studying. Item Comments and examples 1. Target population to whom overall prognosis, prognostic factor(s), or prognostic model under review may apply come from a prospective study, performed in study partici-pants that share most of the clinical characteristics with the target patients for the model (i.e. Etiology/Harm: Questions of negative impact from an intervention or other exposure. Prognostic factors are variables that predict which patients are likely to do better or worse over time. the length of follow-up by which 50% of patients have died) or as event curves (e.g. As prognosis is intrinsically linked to the passage of time, our outcome of research is usually associated with some kind of time period. generalizability of the model) [3]. Gain insight in the pitfalls in prognostic model development with standard statistical techniques. An important part of prognostic research is the development and validation of prognostic models or risk scores. Type of prognosis studies (overall prognosis, prong factor studies, prog model studies) Focus on studies addressing overall prognosis; prognostic factors; model development, model validation or combination. In prognostic studies it is particularly important that the study population is a well- described and representative sample from a relevant and recognisable group of people who have a specified condition or set of characteristics and are at a similar stage in the Typically, results of prognosis studies are reported in one of three ways: as a percentage of the outcome of interest at a particular point in time (e.g. 2 For example, the Perth Community Stroke Study examined the factors that predicted death and disability at 5 years in patients with a first ever stroke who survived the first 30 days. Was the defined representative sample of patients assembled at a common (usually early) point in the course of their disease? PROGNOSTIC STUDIES 1. The PROGNOSIS study is the first multi-center, large-sample study to demonstrate the prognostic value of the Roche Elecsys® preeclampsia test to predict the absence of preeclampsia for one week, and the development of preeclampsia within the subsequent four weeks in women with clinical suspicion of the syndrome. Increasing the knowledge of the roles that prognostic models may play in clinical practice and the critical factors that determine the validity of predictions from a prognostic model. Appraising prognostic studies involves determining the internal validity of the study design and evaluating the influence of systemic errors or bias. 2. Prognosis: Questions of progression of a disease or likelihood of a disease occurring. 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