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Epidemiological methods in diarrhoea studies--an update.

Schmidt, W.P. ; Arnold, B.F. ; Boisson, S. ; Genser, B. ; Luby, S.P. ; Barreto, M.L. ; Clasen, T. ; Cairncross, S. ;
Int J Epidemiol, 2011; 40(6):1678-92
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pub_id
22268237
pubmedid
22268237
ISI
297868500029
reference_type
author
Schmidt, W.P. ; Arnold, B.F. ; Boisson, S. ; Genser, B. ; Luby, S.P. ; Barreto, M.L. ; Clasen, T. ; Cairncross, S. ;
title
Epidemiological methods in diarrhoea studies--an update.
secondary_title
Int J Epidemiol
ISBNISSN
1464-3685
volume
40
number
6
pages
1678-92
year
2011
abstract
BACKGROUND: Diarrhoea remains a leading cause of morbidity and mortality but is difficult to measure in epidemiological studies. Challenges include the diagnosis based on self-reported symptoms, the logistical burden of intensive surveillance and the variability of diarrhoea in space, time and person. METHODS: We review current practices in sampling procedures to measure diarrhoea, and provide guidance for diarrhoea measurement across a range of study goals. Using 14 available data sets, we estimated typical design effects for clustering at household and village/ neighbourhood level, and measured the impact of adjusting for baseline variables on the precision of intervention effect estimates. RESULTS: Incidence is the preferred outcome measure in aetiological studies, health services research and vaccine trials. Repeated prevalence measurements (longitudinal prevalence) are appropriate in high-mortality settings where malnutrition is common, although many repeat measures are rarely useful. Period prevalence is an inadequate outcome if an intervention affects illness duration. Adjusting point estimates for age or diarrhoea at baseline in randomized trials has little effect on the precision of estimates. Design effects in trials randomized at household level are usually <2 (range 1.0–3.2). Design effects for larger clusters (e.g. villages or neighbourhoods) vary greatly among different settings and study designs (range 0.1–25.8). CONCLUSIONS: Using appropriate sampling strategies and outcome measures can improve the efficiency, validity and comparability of diarrhoea studies. Allocating large clusters in cluster randomized trials is compromized by unpredictable design effects and should be carried out only if the research question requires it.
keywords
secondary_author
place_published
publisher
number_of_volumes
tertiary_author
tertiary_title
edition
date
type_of_work
subsidiary_author
alternate_title
call_number
accession_number
custom_1
WOS NEW
custom_2
Unknown
custom_3
custom_4
10.1093/ije/dyr152
custom_5
PMC
custom_6
10
label
2016-10-18
notes
Journal Article
url
author_address
Department for Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK. wolf-peter.schmidt@lshtm.ac.uk
library
22268237 PMC3235024
date_accepted
date_online
created
2012-02-16 17:18:51
modified
2016-07-08 00:00:00
library

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<ArticleId IdType="pmc">PMC3235024</ArticleId>