Article type
Year
Abstract
Background: Trading off desirable and undesirable consequences of alternative patient management strategies requires knowledge of estimates of both relative and absolute measures of effect (AME). It is unclear to what extent and how authors of systematic reviews (SRs) determine and report AME.
Objectives: To determine the proportion of SRs reporting AME and to evaluate how these are derived and interpreted. In particular, we will evaluate the proportion of SR that use relative measures for benefit outcomes and for harm. Additionally, we will test if AM reporting is associated with prespecified study characteristics.
Methods: We will include SRs of interventions that report dichotomous outcomes. We will search MEDLINE for a random stratified sample of Cochrane and non-Cochrane SRs. From a pilot study of 50 SRs, we will calculate the final sample size to test our hypothesis, which is that a considerable proportion of SRs do not report AME and that the methods used are often inadequate. We will determine the proportion of SRs reporting AME and how they are obtained (e.g. meta-analytically combined across studies or computed based on relative effect measures and assumed baseline risk) and reported (e.g. risk difference or number-needed-to-treat). We will also assess how baseline risk was obtained (e.g. as mean or median from included trials or from representative observational studies), and whether authors provided AME for more than one risk group. Finally, we will conduct multivariable logistic regression analyses to examine the relationship of reporting AME with a set of prespecified study characteristics (e.g. type of SR [Cochrane vs not Cochrane], statistical significance or source of funding).
Discussion: The project results will be presented at the Colloquium. Our results will inform the extent of limitations of determining and reporting AME in SRs and lay the foundation for further studies about the implications for decision-making.
Objectives: To determine the proportion of SRs reporting AME and to evaluate how these are derived and interpreted. In particular, we will evaluate the proportion of SR that use relative measures for benefit outcomes and for harm. Additionally, we will test if AM reporting is associated with prespecified study characteristics.
Methods: We will include SRs of interventions that report dichotomous outcomes. We will search MEDLINE for a random stratified sample of Cochrane and non-Cochrane SRs. From a pilot study of 50 SRs, we will calculate the final sample size to test our hypothesis, which is that a considerable proportion of SRs do not report AME and that the methods used are often inadequate. We will determine the proportion of SRs reporting AME and how they are obtained (e.g. meta-analytically combined across studies or computed based on relative effect measures and assumed baseline risk) and reported (e.g. risk difference or number-needed-to-treat). We will also assess how baseline risk was obtained (e.g. as mean or median from included trials or from representative observational studies), and whether authors provided AME for more than one risk group. Finally, we will conduct multivariable logistic regression analyses to examine the relationship of reporting AME with a set of prespecified study characteristics (e.g. type of SR [Cochrane vs not Cochrane], statistical significance or source of funding).
Discussion: The project results will be presented at the Colloquium. Our results will inform the extent of limitations of determining and reporting AME in SRs and lay the foundation for further studies about the implications for decision-making.