[Critical appraisal of systematic reviews of randomised trials in nephrology: theory and practice for interpreting level I evidence].
BACKGROUND
Systematic reviews represent the primary level of evidence (level I evidence) and an excellent answer to causality questions. They should be based upon high quality standards and the critical appraisal of such study design is fundamental.


METHODS
In this review we introduce the primary indicators of quality and guide our readers through the process of critical appraisal of systematic reviews.


RESULTS
The main criteria in critically appraising systematic reviews in nephrology are the adequate presentation of a research question, adequate selection of studies, comprehensiveness of search strategies, the quality assessment of included studies, the fact that all procedures have been performed independently by at least 2 investigators, the exploration of heterogeneity, the type of results and their applicability. In nephrology we still lack a large number of systematic reviews because of the lack of randomised trials.


CONCLUSIONS
Preparing a large number of systematic reviews is an important challenge for the nephrology community. This community should prepare more randomised trials to answer intervention questions and should make an effort to synthesise the evidence in the form of systematic reviews. It is essential that available systematic reviews be critically appraised and their results implemented in the clinical practice whenever they are based on high methodological standards.
Strippoli
G F M
GF
Divisione di Nefrologia, Dipartimento dell'Emergenza e dei Trapianti d'Organo, Universita' degli Studi di Bari - Policlinico, Bari, Italy. gfmstrippoli@katamail.com
Manno
C
C
Schena
F P
FP
D009398:Nephrology; D016032:Randomized Controlled Trials as Topic; D012196:Review Literature as Topic