Lost to follow-up

( Lost of Engl. Follow-up ), the term Lost to follow-up the phenomenon is described in medical statistics that the participants of a scientific study of the observation by the scientists no longer available because the contact between the participants and is canceled scientists. The reasons for this can be, for example, the move to another city or the death of the study participant. It is quite possible that the study participants identified as lost to follow -up has completed the actual study phase and is only stopped coming to the office visits.

To be differentiated, the term lost to follow -up, therefore, strictly speaking, of the so-called drop-outs. As drop-outs study participants are referred to in the medical jargon usually still excrete during the actual study phase of the study.

In practice, however, this distinction can make sometimes difficult because - depending on what type study is - may be some overlap of the two terms. Thus, for example, in an observational study that looks at the long-term effects of maternal nicotine consumption on the overall health development of the child and their observation period is planned for several decades, those study participants who are no longer in itself over the years the study involved both reported to be as drop - outs as well as lost to follow -up. For this reason, in the literature sometimes all study participants whose data were not included in the analysis, referred to as lost to follow -up or as a drop-outs. In individual cases, this must be defined in the respective study final report.