When One is Not Enough: Randomisation by Community
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When One is Not Enough:Randomisation by Community
Neal Alexander
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Why randomise by community or clusterHistorical development of cluster-randomised trials
Emphasis on infectious diseases
Recent and current contributions of TEG
Outline
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Rationale: some interventions are difficult or impossible to allocate or assess individually
Freeman et al 2012 TMIH
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Infections are ‘dependent happenings’
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Pollock 1966 WHO monograph
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Cluster-randomized Trials in PubMed
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Cluster-randomized Trials in PubMed
Ferebee et al (1963): isoniazid prophylaxis in mental institutions
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Cluster-randomized Trials in PubMedThe Gambia Hepatitis Intervention Study (1987)
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Cluster-randomized Trials in PubMedBednets in Gambian villages (Snow et al 1988)
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Cluster-randomized Trials in PubMedIndirect effects (Halloran et al 1991)
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Cluster-randomized Trials in PubMed
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5. Lakeshore 4. Lakeshore
2. Islands
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3. Roadside
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Management of STDs for HIV(Grosskurth et al 1995)
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Lancet 2009
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Compares: community-wide isoniazid preventive therapy vs standard of TB care
1ary endpoint: TB incidence over 12 monthsResults unveiled at CROI 2012 by Fielding & Churchyard
Hostels Mine shaft
Cluster
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% a
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3 m
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2009
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gene
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8 s=0.3s=0.2
inner scale: time in years, assuming three generations per year outer scale: generation number
logi
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e fre
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Design & Analysis of Trials to Compare Genetic Selection Coefficients
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Spatial Analysis of ‘Spillover’
Anaya-Izquierdo et al in prep; trial in Kroeger et al BMJ 2002
km
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