Cargando…

Randomised and non-randomised studies to estimate the effect of community-level public health interventions: definitions and methodological considerations

BACKGROUND: The preferred method to evaluate public health interventions delivered at the level of whole communities is the cluster randomised trial (CRT). The practical limitations of CRTs and the need for alternative methods continue to be debated. There is no consensus on how to classify study de...

Descripción completa

Detalles Bibliográficos
Autor principal: Schmidt, Wolf-Peter
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5590121/
https://www.ncbi.nlm.nih.gov/pubmed/28912825
http://dx.doi.org/10.1186/s12982-017-0063-5
_version_ 1783262471685931008
author Schmidt, Wolf-Peter
author_facet Schmidt, Wolf-Peter
author_sort Schmidt, Wolf-Peter
collection PubMed
description BACKGROUND: The preferred method to evaluate public health interventions delivered at the level of whole communities is the cluster randomised trial (CRT). The practical limitations of CRTs and the need for alternative methods continue to be debated. There is no consensus on how to classify study designs to evaluate interventions, and how different design features are related to the strength of evidence. ANALYSIS: This article proposes that most study designs for the evaluation of cluster-level interventions fall into four broad categories: the CRT, the non-randomised cluster trial (NCT), the controlled before-and-after study (CBA), and the before-and-after study without control (BA). A CRT needs to fulfil two basic criteria: (1) the intervention is allocated at random; (2) there are sufficient clusters to allow a statistical between-arm comparison. In a NCT, statistical comparison is made across trial arms as in a CRT, but treatment allocation is not random. The defining feature of a CBA is that intervention and control arms are not compared directly, usually because there are insufficient clusters in each arm to allow a statistical comparison. Rather, baseline and follow-up measures of the outcome of interest are compared in the intervention arm, and separately in the control arm. A BA is a CBA without a control group. CONCLUSION: Each design may provide useful or misleading evidence. A precise baseline measurement of the outcome of interest is critical for causal inference in all studies except CRTs. Apart from statistical considerations the exploration of pre/post trends in the outcome allows a more transparent discussion of study weaknesses than is possible in non-randomised studies without a baseline measure.
format Online
Article
Text
id pubmed-5590121
institution National Center for Biotechnology Information
language English
publishDate 2017
publisher BioMed Central
record_format MEDLINE/PubMed
spelling pubmed-55901212017-09-14 Randomised and non-randomised studies to estimate the effect of community-level public health interventions: definitions and methodological considerations Schmidt, Wolf-Peter Emerg Themes Epidemiol Analytic Perspective BACKGROUND: The preferred method to evaluate public health interventions delivered at the level of whole communities is the cluster randomised trial (CRT). The practical limitations of CRTs and the need for alternative methods continue to be debated. There is no consensus on how to classify study designs to evaluate interventions, and how different design features are related to the strength of evidence. ANALYSIS: This article proposes that most study designs for the evaluation of cluster-level interventions fall into four broad categories: the CRT, the non-randomised cluster trial (NCT), the controlled before-and-after study (CBA), and the before-and-after study without control (BA). A CRT needs to fulfil two basic criteria: (1) the intervention is allocated at random; (2) there are sufficient clusters to allow a statistical between-arm comparison. In a NCT, statistical comparison is made across trial arms as in a CRT, but treatment allocation is not random. The defining feature of a CBA is that intervention and control arms are not compared directly, usually because there are insufficient clusters in each arm to allow a statistical comparison. Rather, baseline and follow-up measures of the outcome of interest are compared in the intervention arm, and separately in the control arm. A BA is a CBA without a control group. CONCLUSION: Each design may provide useful or misleading evidence. A precise baseline measurement of the outcome of interest is critical for causal inference in all studies except CRTs. Apart from statistical considerations the exploration of pre/post trends in the outcome allows a more transparent discussion of study weaknesses than is possible in non-randomised studies without a baseline measure. BioMed Central 2017-09-07 /pmc/articles/PMC5590121/ /pubmed/28912825 http://dx.doi.org/10.1186/s12982-017-0063-5 Text en © The Author(s) 2017 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. 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.
spellingShingle Analytic Perspective
Schmidt, Wolf-Peter
Randomised and non-randomised studies to estimate the effect of community-level public health interventions: definitions and methodological considerations
title Randomised and non-randomised studies to estimate the effect of community-level public health interventions: definitions and methodological considerations
title_full Randomised and non-randomised studies to estimate the effect of community-level public health interventions: definitions and methodological considerations
title_fullStr Randomised and non-randomised studies to estimate the effect of community-level public health interventions: definitions and methodological considerations
title_full_unstemmed Randomised and non-randomised studies to estimate the effect of community-level public health interventions: definitions and methodological considerations
title_short Randomised and non-randomised studies to estimate the effect of community-level public health interventions: definitions and methodological considerations
title_sort randomised and non-randomised studies to estimate the effect of community-level public health interventions: definitions and methodological considerations
topic Analytic Perspective
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5590121/
https://www.ncbi.nlm.nih.gov/pubmed/28912825
http://dx.doi.org/10.1186/s12982-017-0063-5
work_keys_str_mv AT schmidtwolfpeter randomisedandnonrandomisedstudiestoestimatetheeffectofcommunitylevelpublichealthinterventionsdefinitionsandmethodologicalconsiderations