#Retrospective cohort vs case control trial#

Since you have the outcomes before hand and are looking forward from point of 'exposure' this is classically a retrospective cohort. Then you look back in time for a common 'exposure' AKA risk factor. A suitable research question might be looking. The power of a retrospective cohort would be in the amount of data you have at your disposal (generally patient records or similar), and the relative low cost since the data is already collected. Retrospective cohort: good for studying rare exposures. If you make a study to find out the percentage of smokers among lung cancer patients versus the percentage of smokers among those who do not have lung cancer then this is case-control.Ĭonversely, if you follow smokers and non-smokers in time and see who develop lung cancer or not, then this is a cohort study. In a case-control you have the controls and those already affected. Case control: good for studying rare outcomes. If you only have a whole bunch of cases of diseases and you're trying to match the same amount of controls, then it's case control. If you are following it forward in time, then it's prospective. You can split it by exposure once you know it's a cohort. For example you can say the incidence of pulmonary tuberculosis was xx% in Asian immigrants who immigrated to the US in the period (2005-2010).Ĭlassic example is Smoking and Lung Cancer: If you have a cohort that you are following, then it's a cohort. Note that cohort study can be retrospective i.e you follow the cohort in past time (history) by checking their hospital records for example. Retrospective cohort studies have shown that choice of a general. Case-Control studies are usually but not exclusively retrospective, the opposite is true for cohort studies.

#Retrospective cohort vs case control trial#

You can measure incidence in prospective and retrospective cohort studies. A randomized controlled trial of regional anesthesia combined with propofol sedation. Therefore you use Relative Risk and Attributable Risk. Retrospective Cohort, you are studying the risk factor and see if you can associate a disease to it. All participants (both exposed and unexposed) in a cohort study must be at risk of developing the outcome. Case control studies trace backwards from outcome to exposure. Cohorts track people forward in time from exposure to outcome. Note that Case-Control cannot be prospective because you already have the outcome (disease versus no disease) you are just studying what has lead to this outcome. Historical cohort studies should not be confused with case-control studies (also retrospective). Case-Control Studies are typically done for rare diseases, so you have a rare disease and you go and grab that small number of patients and compare them with a control group and study their history and see if there was a risk factor that might have caused their disease. Elles sont souvent utilisées afin de générer des hypothèses pouvant ensuite être étudiées au moyen d’études de cohorte prospectives ou autres.Case-Control Study, you are studying the disease and see if you can associate risk factors to it. Elles visent à identifier les variables explicatives possibles de l’évolution de l’état de santé et sont utiles pour étudier les maladies ou évolutions de l’état de santé rares. Les études cas-témoins comparent des groupes rétrospectivement. These two versions of retrospective study. Elles sont relativement rapides et simples à réaliser mais ne permettent pas de distinguer la cause de l'effet. The other version of a retrospective study is where the study data are only captured after everything has occurred. Les études transversales sont utilisées afin de déterminer la prévalence. Q1: What is the difference between a retrospective cohort and a cases-control study Case-Control (matched or not): You are investigating the disease or health outcome (you start here, this is determined or already known) and you want to see if you can associate a specific risk factor(s) to the disease. Ces études, qui mesurent les évènements par ordre chronologique, peuvent être utilisées afin de distinguer la cause de l'effet. non-exposed cases) is then compared to another group (controls) closely matched to cases in terms of age, population group. Les études de cohorte sont utilisées afin d’étudier l'incidence, les causes et le pronostic. in particular (in medical research) with the case-control design. View articles or submit your research for publishing. The cohort design is a prospective or (less commonly) retrospective observational. Les études d'observation constituent souvent la seule méthode réalisable pour répondre à des questions relatives à l’étiologie, aux antécédents naturels et au traitement de maladies et cas rares pour lesquels un essai contrôlé randomisé pourrait être contraire à la déontologie. Dove Press is a member of the Open Access Initiative, specializing in peer reviewed Medical Journals. Les études de cohorte, transversales et cas-témoins sont toutes désignées par les termes études d'observation.