Design and level of evidence of studies published in two Brazilian medical journals recently indexed in the ISI Web of Science database

CONTEXT AND OBJECTIVES: The level of evidence and methodological quality of articles published in medical journals are important aids for clinicians in decision-making and also affect journals' impact factor. Although systematic reviews (SR) are considered to represent the highest level of evidence, their methodological quality is not homogeneous and they need to be as carefully assessed as other types of study. This study aimed to assess the design and level of evidence of articles published in 2007, in two recently indexed Brazilian journals (Clinics and Revista da Associação Médica Brasileira), and to evaluate the methodological quality of the SRs. DESIGN AND SETTING: Descriptive study developed in the Brazilian Cochrane Center, Universidade Federal de São Paulo. METHODS: All 289 published articles were classified according to types of study design and level of evidence. The SRs were critically appraised by two evaluators using the AMSTAR tool. RESULTS: The most frequent design types were cross-sectional studies (39.9%), case reports (15.8%), experimental studies (10.8%) and narrative reviews (7.4%). According to the Oxford criteria, 25.6% of the articles were classified as level 4 or 5 evidence, while 2.8% were level 1. SRs represented only 2% of the published articles and their methodological quality scores were low. CONCLUSIONS: The main design types among the published papers were observational and experimental studies and narrative reviews. SRs accounted for a small proportion of the articles and had low methodological scores. Brazilian medical journals need to encourage publication of greater numbers of clinically relevant papers of high methodological quality