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Ethics and Cluster trials

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Ethics and Cluster trials Dr Sarah JL Edwards Senior Lecturer, Research Ethics and Governance Cluster randomized trials are increasingly being used in health and ... – PowerPoint PPT presentation

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Title: Ethics and Cluster trials


1
Ethics and Cluster trials
  • Dr Sarah JL Edwards
  • Senior Lecturer, Research Ethics and Governance

2
  • Cluster randomized trials are increasingly being
    used in health and health services research
  • Illustrate the types of CRTs
  • Identify some ethical issues in review
  • Refer to literature and guidance

Ethics and study design Cluster randomized
trials in health research
3
  • Cluster randomized trials
  • Complex studies
  • Units of randomization are clusters or groups
  • Study intervention may be delivered to
  • the cluster as a unit (cluster-cluster trial)
  • health professionals (professional-cluster trial)
  • individual cluster members (individual-cluster
    trial)
  • Outcomes are measured on individuals.

Ethics and study design Cluster randomized
trials in health research
4
  • COMMIT trial (cluster-cluster trial)
  • Unit of randomisation US and Canadian
    Communities
  • Intervention Multimodal community-level
    intervention to reduce cigarette consumption
    including media and billboard campaign and
    targeted messaging toward smokers from health
    professionals
  • Data collection Interviews with a random sample
    of smokers in each community, the amounts of
    tobacco purchased by people living in the
    intervention and control communities.
  • Result Intervention led to an improved quit rate
    for mild to moderate smokers, with no effect on
    the quit rate of heavy smokers.

Ethics and study design Cluster randomized
trials in health research
5
  • Improving primary care prescribing
    (professional-cluster trial)
  • Unit of randomisation General practitioners in
    Ireland
  • Intervention Personalized summary by mail of
    prescribing practices of antiplatelet and lipid
    lowering drugs plus an educational visit versus
    personalized summary of prescribing practices
    alone
  • Data collection Data on prescribing practices
    from the national pharmacy insurance program
    database. Data on prescribing practices were
    aggregated by physician and contained no
    identifiable information
  • Result Both interventions led to similar
    improvements.

Ethics and study design Cluster randomized
trials in health research
6
  • Cleansing of the umbilical stump in neonates
    (individual-cluster trial)
  • Unit of randomisation Geographical areas in
    Nepal
  • Intervention Community health workers provide
    cleaning the umbilical stump with chlorhexidine
    versus soap and water versus dry stump care
  • Data collection Incidence of infection through
    clinical examination during household visits
    (15,000 infants), neonatal mortality,
    questionnaires about the household and infant
    care
  • Result Chlorhexidine reduced infection of the
    umbilical stump by 75 and neonatal mortality by
    24.

Ethics and study design Cluster randomized
trials in health research
7
  • Rationale important
  • Test how generalisable previous results have been
  • Test cluster level intervention
  • Avoid contamination between trial arms e.g.
    educational or behavioural interventions
  • Capture herd or group effects e.g. vaccines
  • Speed up community roll out of experimental
    medicine

8
  • Right to health and prior evidence of efficacy
    might render cluster trial unjustified
  • Treatment Action Campaign and Others v. Minister
    of Health and Others Constitutional Court of
    South Africa 2002

9
  • In whose interests?
  • Choice and size of cluster
  • Moral status of social groups is not well
    understood
  • Determine group interests average, aggregate?
  • Individual interests each and every best
    interests?

Ethics and study design Cluster randomized
trials in health research
10
  • Who is research subject?
  • CRTs are complex and have multiple levels e.g.,
    hospitals are randomized, health care workers
    receive experimental intervention, and patient
    outcomes are assessed
  • Complicates the identification of research
    participants
  • From whom is informed consent required, if
    anyone?

Ethics and study design Cluster randomized
trials in health research
11
  • Who represents group?
  • In a CRT, clusters may be randomized prior to the
    identification of individual cluster members
  • Is consent to randomization required? If so from
    whom ought it be sought?
  • May gatekeepers provide consent to randomization?
  • Person politically represent group anyway?
  • What are his/her duties?

Ethics and study design Cluster randomized
trials in health research
12
  • Consent to receive intervention
  • In a CRT, the study intervention may be directed
    at the individual or the cluster or both
  • Cluster level interventions (e.g., public
    educational messages or fluoridation of water
    supply) may be difficult for individual cluster
    members to avoid
  • In such cases, refusal of study participation may
    be meaningless.

Ethics and study design Cluster randomized
trials in health research
13
  • 5. Consent to submit data on outcomes
  • In a CRT, the outcomes relate to individuals
    within clusters
  • Individuals may not have consented to
    randomisation of group or to receive experimental
    intervention especially if in control group
  • Risk of contamination may be rationale for using
    cluster design.

Ethics and study design Cluster randomized
trials in health research
14
MRC 2001
  • Ethical and methodological issues following BMJ
    paper 1999 by Edwards et al.

15
Ethics and study design Cluster randomized
trials in health research
16
Acknowledgements
  • HTA for funding in 1999
  • Canadian NIH, Ottowa Statement
  • MRC PhD candidate, Sapfo Lignou, for work on
    ideas of community
  • Wellcome Trust PhD candidate, Elizabeth Oduwo,
    right to health
  • UCL BRC funded work on use of cluster designs
    during pandemic
  • WHO conference 6th June 2014
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