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Non-randomised evaluations of strategies to increase participant retention in randomised controlled trials: a systematic review

BACKGROUND: Retention of participants is essential to ensure the statistical power and internal validity of clinical trials. Poor participant retention reduces power and can bias the estimates of intervention effect. There is sparse evidence from randomised comparisons of effective strategies to ret...

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Autores principales: Elfeky, Adel, Gillies, Katie, Gardner, Heidi, Fraser, Cynthia, Ishaku, Timothy, Treweek, Shaun
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7523052/
https://www.ncbi.nlm.nih.gov/pubmed/32993797
http://dx.doi.org/10.1186/s13643-020-01471-x
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author Elfeky, Adel
Gillies, Katie
Gardner, Heidi
Fraser, Cynthia
Ishaku, Timothy
Treweek, Shaun
author_facet Elfeky, Adel
Gillies, Katie
Gardner, Heidi
Fraser, Cynthia
Ishaku, Timothy
Treweek, Shaun
author_sort Elfeky, Adel
collection PubMed
description BACKGROUND: Retention of participants is essential to ensure the statistical power and internal validity of clinical trials. Poor participant retention reduces power and can bias the estimates of intervention effect. There is sparse evidence from randomised comparisons of effective strategies to retain participants in randomised trials. Currently, non-randomised evaluations of trial retention interventions embedded in host clinical trials are rejected from the Cochrane review of strategies to improve retention because it only included randomised evaluations. However, the systematic assessment of non-randomised evaluations may inform trialists’ decision-making about retention methods that have been evaluated in a trial context.Therefore, we performed a systematic review to synthesise evidence from non-randomised evaluations of retention strategies in order to supplement existing randomised trial evidence. METHODS: We searched MEDLINE, EMBASE, and Cochrane CENTRAL from 2007 to October 2017. Two reviewers independently screened abstracts and full-text articles for non-randomised studies that compared two or more strategies to increase participant retention in randomised trials. The retention trials had to be nested in real ‘host’ trials ( including feasibility studies) but not hypothetical trials. Two investigators independently rated the risk of bias of included studies using the ROBINS-I tool and determined the certainty of evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation) framework. RESULTS: Fourteen non-randomised studies of retention were included in this review. Most retention strategies (in 10 studies) aimed to increase questionnaire response rate. Favourable strategies for increasing questionnaire response rate were telephone follow-up compared to postal questionnaire completion, online questionnaire follow-up compared to postal questionnaire, shortened version of questionnaires versus longer questionnaires, electronically transferred monetary incentives compared to cash incentives, cash compared with no incentive and reminders to non-responders (telephone or text messaging). However, each retention strategy was evaluated in a single observational study. This, together with risk of bias concerns, meant that the overall GRADE certainty was low or very low for all included studies. CONCLUSIONS: This systematic review provides low or very low certainty evidence on the effectiveness of retention strategies evaluated in non-randomised studies. Some strategies need further evaluation to provide confidence around the size and direction of the underlying effect.
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spelling pubmed-75230522020-09-30 Non-randomised evaluations of strategies to increase participant retention in randomised controlled trials: a systematic review Elfeky, Adel Gillies, Katie Gardner, Heidi Fraser, Cynthia Ishaku, Timothy Treweek, Shaun Syst Rev Research BACKGROUND: Retention of participants is essential to ensure the statistical power and internal validity of clinical trials. Poor participant retention reduces power and can bias the estimates of intervention effect. There is sparse evidence from randomised comparisons of effective strategies to retain participants in randomised trials. Currently, non-randomised evaluations of trial retention interventions embedded in host clinical trials are rejected from the Cochrane review of strategies to improve retention because it only included randomised evaluations. However, the systematic assessment of non-randomised evaluations may inform trialists’ decision-making about retention methods that have been evaluated in a trial context.Therefore, we performed a systematic review to synthesise evidence from non-randomised evaluations of retention strategies in order to supplement existing randomised trial evidence. METHODS: We searched MEDLINE, EMBASE, and Cochrane CENTRAL from 2007 to October 2017. Two reviewers independently screened abstracts and full-text articles for non-randomised studies that compared two or more strategies to increase participant retention in randomised trials. The retention trials had to be nested in real ‘host’ trials ( including feasibility studies) but not hypothetical trials. Two investigators independently rated the risk of bias of included studies using the ROBINS-I tool and determined the certainty of evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation) framework. RESULTS: Fourteen non-randomised studies of retention were included in this review. Most retention strategies (in 10 studies) aimed to increase questionnaire response rate. Favourable strategies for increasing questionnaire response rate were telephone follow-up compared to postal questionnaire completion, online questionnaire follow-up compared to postal questionnaire, shortened version of questionnaires versus longer questionnaires, electronically transferred monetary incentives compared to cash incentives, cash compared with no incentive and reminders to non-responders (telephone or text messaging). However, each retention strategy was evaluated in a single observational study. This, together with risk of bias concerns, meant that the overall GRADE certainty was low or very low for all included studies. CONCLUSIONS: This systematic review provides low or very low certainty evidence on the effectiveness of retention strategies evaluated in non-randomised studies. Some strategies need further evaluation to provide confidence around the size and direction of the underlying effect. BioMed Central 2020-09-29 /pmc/articles/PMC7523052/ /pubmed/32993797 http://dx.doi.org/10.1186/s13643-020-01471-x Text en © The Author(s) 2020 Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
spellingShingle Research
Elfeky, Adel
Gillies, Katie
Gardner, Heidi
Fraser, Cynthia
Ishaku, Timothy
Treweek, Shaun
Non-randomised evaluations of strategies to increase participant retention in randomised controlled trials: a systematic review
title Non-randomised evaluations of strategies to increase participant retention in randomised controlled trials: a systematic review
title_full Non-randomised evaluations of strategies to increase participant retention in randomised controlled trials: a systematic review
title_fullStr Non-randomised evaluations of strategies to increase participant retention in randomised controlled trials: a systematic review
title_full_unstemmed Non-randomised evaluations of strategies to increase participant retention in randomised controlled trials: a systematic review
title_short Non-randomised evaluations of strategies to increase participant retention in randomised controlled trials: a systematic review
title_sort non-randomised evaluations of strategies to increase participant retention in randomised controlled trials: a systematic review
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7523052/
https://www.ncbi.nlm.nih.gov/pubmed/32993797
http://dx.doi.org/10.1186/s13643-020-01471-x
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