Systematic reviews in health care: Systematic reviews of evaluations of prognostic variables

Abstract

Identifying relevant publications It is probably more difficult to identify all prognostic studies by searching the literature than it is for randomised trials, which itself is problematic. As yet there is no widely acknowledged optimal strategy for searching the literature for prognostic studies, but search strategies have been developed with either good sensitivity or good specificity 2). Epidemiological studies are more prone to publication bias than randomised trials.4 It is probable that studies showing a strong (often statistically significant) prognostic ability are more likely to be published. Publication bias has recently been shown in studies of Barrett's oesophagus as a risk factor for cancer.5