Assessment of methodological quality of primary studies by systematic reviews: results of the metaquality cross sectional study.
OBJECTIVE
To describe how the methodological quality of primary studies is assessed in systematic reviews and whether the quality assessment is taken into account in the interpretation of results.


METHODS
Cochrane systematic reviews and systematic reviews in paper based journals.


METHODS
965 systematic reviews (809 Cochrane reviews and 156 paper based reviews) published between 1995 and 2002.


RESULTS
The methodological quality of primary studies was assessed in 854 of the 965 systematic reviews (88.5%). This occurred more often in Cochrane reviews than in paper based reviews (93.9% v 60.3%, P < 0.0001). Overall, only 496 (51.4%) used the quality assessment in the analysis and interpretation of the results or in their discussion, with no significant differences between Cochrane reviews and paper based reviews (52% v 49%, P = 0.58). The tools and methods used for quality assessment varied widely.


CONCLUSIONS
Cochrane reviews fared better than systematic reviews published in paper based journals in terms of assessment of methodological quality of primary studies, although they both largely failed to take it into account in the interpretation of results. Methods for assessment of methodological quality by systematic reviews are still in their infancy and there is substantial room for improvement.
Moja
Lorenzo P
LP
Centro Cochrane Italiano, Istituto Mario Negri, Via Eritrea 62, 20157 Milan, Italy.
Telaro
Elena
E
D'Amico
Roberto
R
Moschetti
Ivan
I
Coe
Laura
L
Liberati
Alessandro
A
D003430:Cross-Sectional Studies; D011786:Quality Control; D012107:Research Design / Q000592:standards*; D012196:Review Literature as Topic