gms | German Medical Science

Background: The rapid increase of medical literature has led reviewers to conduct systematic reviews (SR) of systematic reviews as a new publication type, often named “overview”. Up to now little methodological research on overviews has been done. Methodological challenges may be comparable to when using SR in the development of clinical practice guidelines (CPG).

Objective:

1.

To identify methodological challenges in conducting and interpreting overviews;

2.

To draw a comparison to CPG development on the basis of SR;

3.

To discuss the role of overviews in CPG development.

Methods: Methodological challenges were identified and analysed during the preparation of overviews and CPG. A systematic literature search was conducted to identify published overviews. Additional methodological publications dealing with overviews were searched for in order to identify further problems and possible solutions.

Resuts: Many of the methodological standards for SR can be applied to overviews. However, there may be some differences as well as additional challenges: the critical appraisal of included SR, dealing with discordant results, additional searches for current primary studies, evidence synthesis. These results were comparable to problems in CPG development if SR were used as an evidence base.

Discussion and implications for guideline developers/users: Overviews have the potential to save resources. Nevertheless, there are still important methodological questions which have to be answered in general and for different products (CPG, HTA). When using overviews for CPG, it has to be discussed, if data are too compressed to give a useful evidence base, especially with regard to a set of specific key questions.