Retrospective cohort study

A retrospective study (Latin retrospectare look back ') is a term used in clinical research. A study is then referred to as retrospective when starting investigated by the presence of prehistory. In contrast, the data are collected according to the hypothesis formation, especially for the examination thereof in a prospective study.

A typical form of retrospective case-control studies are studies carried out as follows. You select subjects in which this is to be examined event, such as the presence of disease, occurred. To this end, a group is selected from the subjects in which the event ( the disease ) has not occurred, and these. , In its essential for the study of properties such as age, weight and so on, those of the first group should be approximately This is referred to as matching. Subsequently, the subjects are then examined and / or surveyed whether and how much they were exposed to the causative factor to be examined. Using statistical evaluation methods is subsequently analyzed whether the common, rare, or equally often in the first, compared to the second group occurred.

An example: If one wants to investigate the influence of smoking on the development of lung cancer, can be in a hospital all patients who are being treated for lung cancer, ask about their tobacco use and do the same with patients who are treated as lung cancer because of another disease ( also proved possible not because of disease, because for this a strong influence of smoking ). Then you would compare the consumption and figured out that lung cancer patients who smoked significantly more likely than other patients.

Advantages of retrospective studies

Retrospective clinical studies are ethically acceptable and considerably cheaper than experimental studies usually because treatment costs need not be worn. In addition, they can be carried out quite quickly.

Disadvantages of retrospective studies

As retrospective studies, however, are basically non-interventional studies, they have important epistemological disadvantages:

Retrospective studies can only provide little substantial information to optimize patient care.