Systematic reviews published in higher impact clinical journals were of higher quality.
OBJECTIVE
To compare the methodological quality of systematic reviews (SRs) published in high- and low-impact factor (IF) Core Clinical Journals. In addition, we aimed to record the implementation of aspects of reporting, including Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) flow diagram, reasons for study exclusion, and use of recommendations for interventions such as Grading of Recommendations Assessment, Development and Evaluation (GRADE).


METHODS
We searched PubMed for systematic reviews published in Core Clinical Journals between July 1 and December 31, 2012. We evaluated the methodological quality using the Assessment of Multiple Systematic Reviews (AMSTAR) tool.


RESULTS
Over the 6-month period, 327 interventional systematic reviews were identified with a mean AMSTAR score of 63.3% (standard deviation, 17.1%), when converted to a percentage scale. We identified deficiencies in relation to a number of quality criteria including delineation of excluded studies and assessment of publication bias. We found that SRs published in higher impact journals were undertaken more rigorously with higher percentage AMSTAR scores (per IF unit: β = 0.68%; 95% confidence interval: 0.32, 1.04; P < 0.001), a discrepancy likely to be particularly relevant when differences in IF are large.


CONCLUSIONS
Methodological quality of SRs appears to be better in higher impact journals. The overall quality of SRs published in many Core Clinical Journals remains suboptimal.
Oral Growth and Development, Barts and The London School of Medicine and Dentistry, Institute of Dentistry, Queen Mary University of London, Turner St., London E1 2 AD, UK. Electronic address: padhraig.fleming@gmail.com.
Padhraig S
PS
Fleming
Department of Orthodontics, University of Athens, Leoforos Eleftheriou Venizelou 30, Athina 10679, Greece.
Despina
D
Koletsi
Department of Orthodontics, GKT Dental Institute, 82, Camberwell Church St, London SE5 8QZ, UK.
Jadbinder
J
Seehra
Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Freiburgstrasse 7 CH-3010, Bern, Switzerland.
Nikolaos
N
Pandis
D055811:Journal Impact Factor; D017594:Publication Bias; D011643:Publishing / Q000592:standards*; D012107:Research Design / Q000592:standards; D012196:Review Literature as Topic
AMSTAR; Impact factor; Meta-analysis; Methodological quality; Review; Systematic