Hannah Ewald1, Irma Klerings2, Gernot Wagner2, Thomas L Heise3, Andreea Iulia Dobrescu2, Susan Armijo-Olivo4, Jan M Stratil5, Stefan K Lhachimi3, Tarquin Mittermayr6, Gerald Gartlehner7, Barbara Nussbaumer-Streit2, Lars G Hemkens8. 1. Department of Clinical Research, Basel Institute for Clinical Epidemiology and Biostatistics, University Hospital Basel, University of Basel, Basel, Switzerland; Swiss Tropical and Public Health Institute, Basel, Switzerland; University Medical Library, University of Basel, Basel, Switzerland. 2. Cochrane Austria, Department of Evidence-based Medicine and Evaluation, Danube University Krems, Krems, Austria. 3. Leibniz Institute for Prevention Research and Epidemiology (BIPS), Bremen, Germany; Institute for Public Health and Nursing Research (IPP), Health Sciences Bremen, University of Bremen, Bremen, Germany. 4. Faculty of Rehabilitation Medicine, University of Alberta & Institute of Health Economics, Edmonton, Alberta, Canada; University of Applied Sciences, Faculty of Business and Social Sciences, Osnabrück, Germany. 5. Institute for Medical Information Processing, Biometry and Epidemiology, Pettenkofer School of Public Health, LMU Munich, Munich, Germany. 6. Ludwig Boltzmann Institute for Health Technology Assessment, Austria. 7. Cochrane Austria, Department of Evidence-based Medicine and Evaluation, Danube University Krems, Krems, Austria; RTI International, Research Triangle Park, NC, USA. 8. Department of Clinical Research, Basel Institute for Clinical Epidemiology and Biostatistics, University Hospital Basel, University of Basel, Basel, Switzerland. Electronic address: Lars.Hemkens@usb.ch.
Abstract
OBJECTIVES: The objective of this study was to assess the agreement of treatment effect estimates from meta-analyses based on abbreviated or comprehensive literature searches. STUDY DESIGN AND SETTING: This was a meta-epidemiological study. We abbreviated 47 comprehensive Cochrane review searches and searched MEDLINE/Embase/CENTRAL alone, in combination, with/without checking references (658 new searches). We compared one meta-analysis from each review with recalculated ones based on abbreviated searches. RESULTS: The 47 original meta-analyses included 444 trials (median 6 per review [interquartile range (IQR) 3-11]) with 360045 participants (median 1,371 per review [IQR 685-8,041]). Depending on the search approach, abbreviated searches led to identical effect estimates in 34-79% of meta-analyses, to different effect estimates with the same direction and level of statistical significance in 15-51%, and to opposite effects (or effects could not be estimated anymore) in 6-13%. The deviation of effect sizes was zero in 50% of the meta-analyses and in 75% not larger than 1.07-fold. Effect estimates of abbreviated searches were not consistently smaller or larger (median ratio of odds ratio 1 [IQR 1-1.01]) but more imprecise (1.02-1.06-fold larger standard errors). CONCLUSION: Abbreviated literature searches often led to identical or very similar effect estimates as comprehensive searches with slightly increased confidence intervals. Relevant deviations may occur.
OBJECTIVES: The objective of this study was to assess the agreement of treatment effect estimates from meta-analyses based on abbreviated or comprehensive literature searches. STUDY DESIGN AND SETTING: This was a meta-epidemiological study. We abbreviated 47 comprehensive Cochrane review searches and searched MEDLINE/Embase/CENTRAL alone, in combination, with/without checking references (658 new searches). We compared one meta-analysis from each review with recalculated ones based on abbreviated searches. RESULTS: The 47 original meta-analyses included 444 trials (median 6 per review [interquartile range (IQR) 3-11]) with 360045 participants (median 1,371 per review [IQR 685-8,041]). Depending on the search approach, abbreviated searches led to identical effect estimates in 34-79% of meta-analyses, to different effect estimates with the same direction and level of statistical significance in 15-51%, and to opposite effects (or effects could not be estimated anymore) in 6-13%. The deviation of effect sizes was zero in 50% of the meta-analyses and in 75% not larger than 1.07-fold. Effect estimates of abbreviated searches were not consistently smaller or larger (median ratio of odds ratio 1 [IQR 1-1.01]) but more imprecise (1.02-1.06-fold larger standard errors). CONCLUSION: Abbreviated literature searches often led to identical or very similar effect estimates as comprehensive searches with slightly increased confidence intervals. Relevant deviations may occur.
Authors: Benjamin Djulbegovic; Muhammad Muneeb Ahmed; Iztok Hozo; Despina Koletsi; Lars Hemkens; Amy Price; Rachel Riera; Paulo Nadanovsky; Ana Paula Pires Dos Santos; Daniela Melo; Ranjan Pathak; Rafael Leite Pacheco; Luis Eduardo Fontes; Enderson Miranda; David Nunan Journal: J Eval Clin Pract Date: 2022-01-28 Impact factor: 2.336