Dalla Lana School of Public Health
Permanent URI for this communityhttps://hdl.handle.net/1807/67751
The Dalla Lana School of Public Health (DLSPH), a Faculty of the University of Toronto, is a regional and global leader in public health education, research and service, with the largest concentrations of academic population and public health researchers in Canada and over $30 million in research funding per year.
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Browsing Dalla Lana School of Public Health by Author "Ahmadzai, Nadera"
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Item Flaws in the application and interpretation of statistical analyses in systematic reviews of therapeutic interventions were common: a cross-sectional analysis(Elsevier, 2017-12-02) Page, Matthew J; Altman, Douglas G; McKenzie, Joanne E; Shamseer, Larissa; Ahmadzai, Nadera; Wolfe, Dianna; Yazdi, Fatemeh; Catalá-López, Ferrán; Tricco, Andrea C; Moher, DavidObjectives: The objective of the study was to investigate the application and interpretation of statistical analyses in a cross-section of systematic reviews (SRs) of therapeutic interventions, without restriction by journal, clinical condition, or specialty. Study Design and Setting: We evaluated a random sample of SRs assembled previously, which were indexed in MEDLINE® during February 2014, focused on a treatment or prevention question, and reported at least one meta-analysis. The reported statistical methods used in each SR were extracted from articles and online appendices by one author, with a 20% random sample extracted in duplicate. Results: We evaluated 110 SRs; 78/110 (71%) were non-Cochrane SRs and 55/110 (50%) investigated a pharmacological intervention. The SRs presented a median of 13 (interquartile range: 5–27) meta-analytic effects. When considering the index (primary or first reported) meta-analysis of each SR, just over half (62/110 [56%]) used the random-effects model, but few (5/62 [8%]) interpreted the meta-analytic effect correctly (as the average of the intervention effects across all studies). A statistical test for funnel plot asymmetry was reported in 17/110 (15%) SRs; however, in only 4/17 (24%) did the test include the recommended number of at least 10 studies of varying size. Subgroup analyses accompanied 42/110 (38%) index meta-analyses, but findings were not interpreted with respect to a test for interaction in 29/42 (69%) cases, and the issue of potential confounding in the subgroup analyses was not raised in any SR. Conclusions: There is scope for improvement in the application and interpretation of statistical analyses in SRs of therapeutic interventions. The involvement of statisticians on the SR team and establishment of partnerships between researchers with specialist expertise in SR methods and journal editors may help overcome these shortcomings.Item Reproducible research practices are underused in systematic reviews of biomedical interventions(Elsevier, 2017-11-04) Page, Matthew J; Altman, Douglas G; Shamseer, Larissa; McKenzie, Joanne E; Ahmadzai, Nadera; Wolfe, Dianna; Yazdi, Fatemeh; Catalá-López, Ferrán; Tricco, Andrea C; Moher, DavidObjectives: To evaluate how often reproducible research practices, which allow others to recreate the findings of studies, given the original data, are used in systematic reviews (SRs) of biomedical research. Study Design and Setting: We evaluated a random sample of SRs indexed in MEDLINE during February 2014, which focused on a therapeutic intervention and reported at least one meta-analysis. Data on reproducible research practices in each SR were extracted using a 26-item form by one author, with a 20% random sample extracted in duplicate. We explored whether the use of reproducible research practices was associated with an SR being a Cochrane review, as well as with the reported use of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Results: We evaluated 110 SRs of therapeutic interventions, 78 (71%) of which were non-Cochrane SRs. Across the SRs, there were 2,139 meta-analytic effects (including subgroup meta-analytic effects and sensitivity analyses), 1,551 (73%) of which were reported in sufficient detail to recreate them. Systematic reviewers reported the data needed to recreate all meta-analytic effects in 72 (65%) SRs only. This percentage was higher in Cochrane than in non-Cochrane SRs (30/32 [94%] vs. 42/78 [54%]; risk ratio 1.74, 95% confidence interval 1.39–2.18). Systematic reviewers who reported imputing, algebraically manipulating, or obtaining some data from the study author/sponsor infrequently stated which specific data were handled in this way. Only 33 (30%) SRs mentioned access to data sets and statistical code used to perform analyses. Conclusion: Reproducible research practices are underused in SRs of biomedical interventions. Adoption of such practices facilitates identification of errors and allows the SR data to be reanalyzed.