Level of evidence in high impact surgical literature: the way forward

Evidence-based medicine stipulates that clinical decision-making should revolve around scientific evidence. The goal of the present study is to evaluate the methodological quality of surgical research recently published in JAMA Surgery, International Journal of Surgery, and British Journal of Surgery, the three surgical journals with the highest impact factor. An electronic search of the PUBMED database was performed to retrieve all articles published in the JAMA Surgery, International Journal of Surgery, and British Journal of Surgery in the year 2022. Three authors independently reviewed all retrieved articles and methodological designs of the publications were analyzed and rated using a modification of the Oxford Centre for Evidence-Based Medicine Levels of Evidence (Oxford Levels of Evidence scale). The initial search identified 1236 articles of which 809 were excluded after title and abstract screening. The remaining 427 underwent full text/methods read, of which 164 did not meet the inclusion/exclusion criteria. A total of 273 studies were included in the analysis. The average level of evidence was 2.5 +/- 0.8 across all studies assessed. The majority of study designs were comprised of retrospective cohorts (n = 119), prospective cohorts (n = 47), systematic reviews of non RCTs (n = 39), and RCTs (n = 37). There was no significant difference in the average level of evidence between the top three journals (p = 0.50). Most clinical studies in the highest impact factor surgical journals are of level III evidence, consistent with earlier literature. However, our analysis demonstrates a relatively higher percentage of LOE I and II compared to what was previously published in the literature.