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Outcomes in Cochrane Systematic Reviews Addressing Four Common Eye Conditions: An Evaluation of Completeness and Comparability

INTRODUCTION: Choice of outcomes is critical for clinical trialists and systematic reviewers. It is currently unclear how systematic reviewers choose and pre-specify outcomes for systematic reviews. Our objective was to assess the completeness of pre-specification and comparability of outcomes in al...

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Autores principales: Saldanha, Ian J., Dickersin, Kay, Wang, Xue, Li, Tianjing
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4199623/
https://www.ncbi.nlm.nih.gov/pubmed/25329377
http://dx.doi.org/10.1371/journal.pone.0109400
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author Saldanha, Ian J.
Dickersin, Kay
Wang, Xue
Li, Tianjing
author_facet Saldanha, Ian J.
Dickersin, Kay
Wang, Xue
Li, Tianjing
author_sort Saldanha, Ian J.
collection PubMed
description INTRODUCTION: Choice of outcomes is critical for clinical trialists and systematic reviewers. It is currently unclear how systematic reviewers choose and pre-specify outcomes for systematic reviews. Our objective was to assess the completeness of pre-specification and comparability of outcomes in all Cochrane reviews addressing four common eye conditions. METHODS: We examined protocols for all Cochrane reviews as of June 2013 that addressed glaucoma, cataract, age-related macular degeneration (AMD), and diabetic retinopathy (DR). We assessed completeness and comparability for each outcome that was named in ≥25% of protocols on those topics. We defined a completely-specified outcome as including information about five elements: domain, specific measurement, specific metric, method of aggregation, and time-points. For each domain, we assessed comparability in how individual elements were specified across protocols. RESULTS: We identified 57 protocols addressing glaucoma (22), cataract (16), AMD (15), and DR (4). We assessed completeness and comparability for five outcome domains: quality-of-life, visual acuity, intraocular pressure, disease progression, and contrast sensitivity. Overall, these five outcome domains appeared 145 times (instances). Only 15/145 instances (10.3%) were completely specified (all five elements) (median = three elements per outcome). Primary outcomes were more completely specified than non-primary (median = four versus two elements). Quality-of-life was least completely specified (median = one element). Due to largely incomplete outcome pre-specification, conclusive assessment of comparability in outcome usage across the various protocols per condition was not possible. DISCUSSION: Outcome pre-specification was largely incomplete; we encourage systematic reviewers to consider all five elements. This will indicate the importance of complete specification to clinical trialists, on whose work systematic reviewers depend, and will indirectly encourage comparable outcome choice to reviewers undertaking related research questions. Complete pre-specification could improve efficiency and reduce bias in data abstraction and analysis during a systematic review. Ultimately, more completely specified and comparable outcomes could make systematic reviews more useful to decision-makers.
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spelling pubmed-41996232014-10-21 Outcomes in Cochrane Systematic Reviews Addressing Four Common Eye Conditions: An Evaluation of Completeness and Comparability Saldanha, Ian J. Dickersin, Kay Wang, Xue Li, Tianjing PLoS One Research Article INTRODUCTION: Choice of outcomes is critical for clinical trialists and systematic reviewers. It is currently unclear how systematic reviewers choose and pre-specify outcomes for systematic reviews. Our objective was to assess the completeness of pre-specification and comparability of outcomes in all Cochrane reviews addressing four common eye conditions. METHODS: We examined protocols for all Cochrane reviews as of June 2013 that addressed glaucoma, cataract, age-related macular degeneration (AMD), and diabetic retinopathy (DR). We assessed completeness and comparability for each outcome that was named in ≥25% of protocols on those topics. We defined a completely-specified outcome as including information about five elements: domain, specific measurement, specific metric, method of aggregation, and time-points. For each domain, we assessed comparability in how individual elements were specified across protocols. RESULTS: We identified 57 protocols addressing glaucoma (22), cataract (16), AMD (15), and DR (4). We assessed completeness and comparability for five outcome domains: quality-of-life, visual acuity, intraocular pressure, disease progression, and contrast sensitivity. Overall, these five outcome domains appeared 145 times (instances). Only 15/145 instances (10.3%) were completely specified (all five elements) (median = three elements per outcome). Primary outcomes were more completely specified than non-primary (median = four versus two elements). Quality-of-life was least completely specified (median = one element). Due to largely incomplete outcome pre-specification, conclusive assessment of comparability in outcome usage across the various protocols per condition was not possible. DISCUSSION: Outcome pre-specification was largely incomplete; we encourage systematic reviewers to consider all five elements. This will indicate the importance of complete specification to clinical trialists, on whose work systematic reviewers depend, and will indirectly encourage comparable outcome choice to reviewers undertaking related research questions. Complete pre-specification could improve efficiency and reduce bias in data abstraction and analysis during a systematic review. Ultimately, more completely specified and comparable outcomes could make systematic reviews more useful to decision-makers. Public Library of Science 2014-10-16 /pmc/articles/PMC4199623/ /pubmed/25329377 http://dx.doi.org/10.1371/journal.pone.0109400 Text en © 2014 Saldanha et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Saldanha, Ian J.
Dickersin, Kay
Wang, Xue
Li, Tianjing
Outcomes in Cochrane Systematic Reviews Addressing Four Common Eye Conditions: An Evaluation of Completeness and Comparability
title Outcomes in Cochrane Systematic Reviews Addressing Four Common Eye Conditions: An Evaluation of Completeness and Comparability
title_full Outcomes in Cochrane Systematic Reviews Addressing Four Common Eye Conditions: An Evaluation of Completeness and Comparability
title_fullStr Outcomes in Cochrane Systematic Reviews Addressing Four Common Eye Conditions: An Evaluation of Completeness and Comparability
title_full_unstemmed Outcomes in Cochrane Systematic Reviews Addressing Four Common Eye Conditions: An Evaluation of Completeness and Comparability
title_short Outcomes in Cochrane Systematic Reviews Addressing Four Common Eye Conditions: An Evaluation of Completeness and Comparability
title_sort outcomes in cochrane systematic reviews addressing four common eye conditions: an evaluation of completeness and comparability
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4199623/
https://www.ncbi.nlm.nih.gov/pubmed/25329377
http://dx.doi.org/10.1371/journal.pone.0109400
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