[Meta-analysis of epidemiologic studies].

BACKGROUND

A metaanalysis is often performed if risk assessment with available epidemiological data is not sensible. The results of these analyses serve mainly to quantify the risk of weak associations.

MATERIAL AND METHODS

In this paper we describe methodologic issues of this approach with emphasis on the difference between metaanalysis from published data and from individual patient records. As an example we discuss studies on oral contraceptives and breast cancer. Limits of metaanalysis from published data are given.

CONCLUSION

Although metaanalysis with individual data may be cost- and time-consuming their results are more reliable.