Systematic reviews and meta-analysis published in indexed Portuguese medical journals: time trends and critical appraisal

INTRODUCTION: Over the last years, the number of systematic reviews published is steadily increasing due to the global interest in this type of evidence synthesis. However, little is known about the characteristics of this research published in Portuguese medical journals. This study aims to evaluate the publication trends and overall quality of these systematic reviews. MATERIAL AND METHODS: This was a methodological study. We aimed the most visible Portuguese medical journals indexed in MEDLINE. Systematic reviews were identified through an electronic search (through PUBMED). We included systematic reviews published up to August 2020. Systematic reviews selection and data extraction were done independently by three authors. The overall quality critical appraisal using the A MeaSurement Tool to Assess systematic Reviews (AMSTAR-2) was independently assessed by three authors. Disagreements were solved by consensus. RESULTS: Sixty-six systematic reviews published in 5 Portuguese medical journals were included. Most (n = 53; 80.3%) were systematic reviews without meta-analysis. Up to 2010 there was a steady increase in the number of systematic reviews published, followed by a period of great variability of publication, ranging from 1 to 10 in a given year. According to the systematic reviews’ typology, most have been predominantly conducted to assess the effectiveness/efficacy of health interventions (n = 27; 40.9%). General and Internal Medicine (n = 20; 30.3%) was the most addressed field. Most systematic reviews (n = 46; 69.7%) were rated as being of “critically low-quality”. CONCLUSIONS: There were consistent flaws in the methodological quality report of the systematic reviews included, particularly in establishing a prior protocol and not assessing the potential impact of the risk of bias on the results. Through the years, the number of systematic reviews published increased, yet their quality is suboptimal. There is a need to improve the reporting of systematic reviews in Portuguese medical journals, which can be achieved by better adherence to quality checklists/tools. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12874-022-01591-z.