Ringsten M, Färnqvist K, Bruschettini M, Johansson M
Cochrane Sweden, Department of Research, Development, Education and Innovation, Skåne University Hospital Lund University Lund Sweden.
Molecular Medicine and Surgery Karolinska Institute Stockholm Sweden.
Cochrane Evid Synth Methods. 2025 Jan 9;3(1):e70015. doi: 10.1002/cesm.70015. eCollection 2025 Jan.
A systematic review (SR) attempts to find, assess and summarize all the empirical evidence to answer a specific research question. We aim to explore to what extent reviews are included in doctoral theses from all universities with a medical faculty in Sweden, and to describe the type, topic and assess the methodological quality of the reviews.
Duplicate assessors independently searched local and national repositories for doctoral theses published in 2021 within all seven medical faculties in Sweden, and categorized identified reviews based on review type, topic, and methodological quality using AMSTAR-2.
5.4% (45/852) of all doctoral theses included a review, and 1.3% (45/3461) of all included studies were reviews. Of these, two thirds (31) were SRs and the rest (14) were broader 'big picture' reviews. The most common topics were interventions (42%) and exposure/etiology (32%), with no reviews of diagnostic tests. The majority of the SRs had very low (71%) or low (19%) quality, and few reached a high (7%) or moderate (3%) quality. The most common issues were limitations with protocols, limited search strategies, and failure to account for risk of bias in drawn conclusions.
Few doctoral students included SRs in their theses, and the few SRs included in doctoral theses generally had a low quality. There is no consensus on the appropriate proportion of doctoral thesis including a SR. We argue that conducting a SR within a doctoral thesis can reduce redundant, harmful and unethical research, identify knowledge gaps, and help the doctoral student obtain important skills to conduct and use research.
系统评价（SR）旨在查找、评估和总结所有实证证据，以回答特定的研究问题。我们旨在探究瑞典所有设有医学院的大学的博士论文中纳入系统评价的程度，并描述这些评价的类型、主题以及评估其方法学质量。
由两名评估人员独立在地方和国家数据库中搜索2021年在瑞典所有七个医学院发表的博士论文，并使用AMSTAR-2根据评价类型、主题和方法学质量对所识别出的系统评价进行分类。
所有博士论文中有5.4%（45/852）纳入了系统评价，所有纳入研究中有1.3%（45/3461）是系统评价。其中，三分之二（31篇）是系统评价，其余（14篇）是更宽泛的“全景式”评价。最常见的主题是干预措施（42%）和暴露/病因（32%），没有关于诊断试验的系统评价。大多数系统评价质量非常低（71%）或低（19%），只有少数达到高（7%）或中等（3%）质量。最常见的问题是方案存在局限性、检索策略有限以及在得出结论时未考虑偏倚风险。
很少有博士生在其论文中纳入系统评价，且博士论文中纳入的少数系统评价质量普遍较低。对于博士论文中纳入系统评价的适当比例尚无共识。我们认为，在博士论文中进行系统评价可以减少冗余、有害和不道德的研究，识别知识空白，并帮助博士生获得开展和运用研究的重要技能。
