Introduction
The topic of venous thromboembolism following shoulder surgery is present in various studies, including retrospective analyses and prospective cohort prognosis studies. The risk of bias in these studies has a high potential due to the lack of randomized trials and systematic reviews. The six selected case-control studies and cohorts were investigated with the help of the Methodological Index for Non-Randomized Studies (MINORS). MINORS is a tool for appreciating the quality of the data reported in articles that use observations and prospective methodologies. The present paper considers the potential risks of the chosen articles’ content.
Methods
MINORS is an instrument designed to appraise the quality of quantitative studies. It contains 12 items – eight of them apply to all studies, and the remaining four are only used to examine comparative research (Slim et al., 2003). The tool’s items inquire about the article’s aims, patient inclusion criteria, data collection, appropriate endpoints, unbiased assessment, follow-up quality, and calculation of the study size. The additional block of questions considers whether comparative studies use an evidence-supported control group that is contemporary to, comparable to, and adequate for the intervention group (Slim et al., 2003). The two sets of statements consider how non-randomized articles represent the collection and interpretation of information.
MINORS is a quantitative tool that represents the quality of each element with a number. It employs a 3-point scale, where “0” refers to the information not being documented in the article, “1” shows that some data is reported but it is inadequate, and “2” means that the data is clearly stated and is acceptable (Slim et al., 2003). As a result, studies can have up to 16 or 24 points in total. The quality review of the articles and the potential for biases was conducted by two authors independently. Any differences in opinions were discussed following the rating and brought to a consensus.
Results: Risk of Bias for Non-Randomized Studies
Six articles selected for investigation were concerned with the outcomes of shoulder surgery and the development of venous thromboembolism (VTE) or deep vein thrombosis (DVT). The chosen studies employed quantitative methodologies, which are appropriate for MINORS assessment. The evaluation results are presented in Table 1. Two of the six research papers do not contain any comparative investigations, which means that the last four questions in the tool are not applicable to them. Other studies perform some comparisons and are evaluated using all 12 items.
Table 1. MINORS Tool for Selected Non-Randomized Studies.
The assessment of the chosen studies shows that many do not provide complete and adequate information to exclude potential biases. One of the most reliable articles is the one by Alyea et al. (2019), who report much of the needed data and have the longest follow-up period. Nonetheless, as a retrospective study, this research fails to provide prospective data collection. Furthermore, the authors do not employ blind data assessment and do not provide any justification for non-blind measurement. Lastly, there are no transparent statements discussing follow-up loss rates.
Considering the chosen articles, significant risks of measurement bias exist in all studies as none of them engage in unbiased, randomized, and blind evaluation of the results to arrive at the conclusions. Therefore, the discussed outcomes must be taken into consideration with caution. Furthermore, comparative studies display a lack of transparency in choosing their control and intervention groups – only one of the four research papers identifies a control group with procedures supported by evidence that is also contemporary and equivalent (Alyea et al., 2019). Moreover, most articles do not have long follow-up times, with most returning to collect data from patient records after 90 days since the intervention.
Conclusion
In conclusion, the use of MINORS to examine the quality of non-randomized studies reveals a significant presence of calculation and selection bias in the chosen studies. The articles have different degrees of transparency and complete data representation, with some failing to adequately show group comparison, follow-up information, and impartial assessment. The absence of randomized trials and unbiased calculations in the present scholarship raises the issue of low-quality data.
References
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