Article type
Year
Abstract
Background:
Blood services play a critical role in healthcare by providing a safe, adequate and cost-effective supply of blood components. To achieve this, donors demonstrating certain characteristics that are considered to increase the risk of complications in the transfusion recipient, are deferred. Therefore, systematic reviews examining risk factors for blood safety (e.g. having tattoos, vaccination or blood disorder) are essential to set appropriate, up-to-date and evidence-based donor eligibly criteria. However, such reviews are challenging to conduct.
Objectives:
To give an overview of the methodological challenges related to the conduct of systematic reviews of risk factors.
Methods:
Literature reviews on risk factors were performed.
Results:
The following challenges were encountered during multiple stages of the review process. Firstly, we encountered selective reporting of statistically significant risk factors in the abstract. This can be solved by the inclusion of other risk factors than the factor of interest in the search strategy, and the incorporation of general wording about risk factors. As a result, the search will reach high sensitivity but specificity will be negatively influenced. Secondly, the study designs used for risk factor analysis (e.g. cross-sectional studies) differ from experimental designs and are more prone to bias. As a consequence, the initial level of evidence will be low, according to the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. Finally, different approaches to control for confounding (e.g. by study type and/or by post-hoc statistical analysis) are being used. Therefore, the evidence reviewer will often not be able to pool data or to make final conclusions about independent risk factors.
Conclusions:
To inform policy makers in transfusion, highly sensitive literature searches concerning risk factors for blood safety are needed. Due to reporting issues, experimental flaws and statistical differences, systematically reviewing of risk factors is not only subjected to higher risk of bias but is also time- and cost-intensive.
Blood services play a critical role in healthcare by providing a safe, adequate and cost-effective supply of blood components. To achieve this, donors demonstrating certain characteristics that are considered to increase the risk of complications in the transfusion recipient, are deferred. Therefore, systematic reviews examining risk factors for blood safety (e.g. having tattoos, vaccination or blood disorder) are essential to set appropriate, up-to-date and evidence-based donor eligibly criteria. However, such reviews are challenging to conduct.
Objectives:
To give an overview of the methodological challenges related to the conduct of systematic reviews of risk factors.
Methods:
Literature reviews on risk factors were performed.
Results:
The following challenges were encountered during multiple stages of the review process. Firstly, we encountered selective reporting of statistically significant risk factors in the abstract. This can be solved by the inclusion of other risk factors than the factor of interest in the search strategy, and the incorporation of general wording about risk factors. As a result, the search will reach high sensitivity but specificity will be negatively influenced. Secondly, the study designs used for risk factor analysis (e.g. cross-sectional studies) differ from experimental designs and are more prone to bias. As a consequence, the initial level of evidence will be low, according to the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. Finally, different approaches to control for confounding (e.g. by study type and/or by post-hoc statistical analysis) are being used. Therefore, the evidence reviewer will often not be able to pool data or to make final conclusions about independent risk factors.
Conclusions:
To inform policy makers in transfusion, highly sensitive literature searches concerning risk factors for blood safety are needed. Due to reporting issues, experimental flaws and statistical differences, systematically reviewing of risk factors is not only subjected to higher risk of bias but is also time- and cost-intensive.