The need for caution in interpreting high quality systematic reviews

摘要

The emergence of systematic reviews raised hopes of a new era for the objective appraisal of evidence available on a given topic. Such reviews promised a synthesis of trial results, which could be conflicting, and an escape from the personal bias inherent in traditional reviews and expert opinion. As the discipline of systematic reviews has evolved, however, two new problems have arisen: the quality of reviews is variable; and two or more systematic reviews on the same topic may arrive at different conclusions, raising questions on the validity or the relevance of the conclusions. Moreover, adherence to a "checklist" system when appraising trials may overlook important clinical details in the original trials and so reduce the validity of the review. I uncovered this last shortcoming when I recendy conducted a study of three systematic reviews; the study is reported here.