University of Applied Sciences Bielefeld, Faculty of Business, CareTech OWL - Center for Health, Welfare and Technology, Bielefeld, Germany.
PLoS One. 2022 May 9;17(5):e0267883. doi: 10.1371/journal.pone.0267883. eCollection 2022.
Analyses of clinical trial registries (CTRs) offer insights into methodological problems of published research studies, e.g., non-publication and outcome-switching. Here, we use CTRs as a tool to evaluate clinical studies conducted in Germany and test how their registration quality is associated with time and structural factors: Coordinating Centers for Clinical Trials (KKS) and Universities of Excellence.
We searched ClinicalTrials.gov, the DRKS, and the ICTRP for clinical trials recruiting participants in Germany. As a measure for the methodological quality, we assessed the proportion of trials that were pre-registered. In addition, the registration quality and availability of publications relating to the trials were manually assessed for a sample (n = 639). Also, the influence of the structural factors was tested using regression models.
We identified 35,912 trials that were conducted in Germany. 59% of trials were pre-registered. Surprisingly, Universities of Excellence had lower pre-registration rates. The influence of KKS was unclear and also difficult to test. Interventional trials were more likely to be pre-registered. Registration quality improved over time and was higher in interventional trials. As of early 2021, 49% of trials that started until the end of 2015 have published scientific articles. 187 of 502 studies on ClinicalTrials.gov for which we found published articles did not reference any in the registry entry.
The structural predictors did not show consistent relationships with the various outcome variables. However, the finding that the study type and time were related to better registration quality suggests that regulatory regimes may have an impact. Limitations of this non-pre-registered study were that no modifications to registry entries were tracked and the coarse measure of KKS involvement.
对临床试验注册库（CTR）的分析可以深入了解已发表研究的方法学问题，例如不发表和结果转换。在这里，我们使用 CTR 作为一种工具来评估在德国进行的临床研究，并检验其注册质量与时间和结构因素的关系：临床试验协调中心（KKS）和卓越大学。
我们在 ClinicalTrials.gov、DRKS 和 ICTRP 中搜索了在德国招募参与者的临床试验。作为衡量方法学质量的标准，我们评估了预先注册试验的比例。此外，我们还对 639 个样本的临床试验的注册质量和相关出版物的可用性进行了手动评估。同时，我们还使用回归模型检验了结构因素的影响。
我们确定了在德国进行的 35912 项试验。59%的试验是预先注册的。令人惊讶的是，卓越大学的预先注册率较低。KKS 的影响不明确，也难以测试。干预性试验更有可能预先注册。注册质量随着时间的推移而提高，且干预性试验的注册质量更高。截至 2021 年初，截至 2015 年底结束的试验中有 49%已发表科学文章。在 ClinicalTrials.gov 上对我们发现有发表文章的 502 项研究中的 187 项进行了研究，这些研究没有引用注册库条目中的任何内容。
结构预测因素与各种结果变量之间没有一致的关系。然而，研究类型和时间与更好的注册质量相关的发现表明，监管制度可能会产生影响。本非预先注册研究的局限性在于，未跟踪对注册表条目的任何修改，以及对 KKS 参与情况的粗略衡量。
