Differences Between Seven Measures of Self-Reported Numbers of Clients of Female Sex Workers in Southern India: Implications for Individual- and Population-Level Analysis
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Quantifying sexual activity of sub-populations with high-risk sexual behaviour is important in understanding HIV epidemiology. This study examined inconsistency of seven outcomes measuring self-reported clients per month (CPM) of female sex workers (FSWs) in southern India and implications for individual/population-level analysis. Multivariate negative binomial regression was used to compare key social/environmental factors associated with each outcome. A transmission dynamics model was used to assess the impact of differences between outcomes on population-level FSW/client HIV prevalence. Outcomes based on ‘clients per last working day’ produced lower estimates than those based on ‘clients per typical day’. Although the outcomes were strongly correlated, their averages differed by approximately two-fold (range 39.0–79.1 CPM). The CPM measure chosen did not greatly influence standard epidemiological ‘risk factor’ analysis. Differences across outcomes influenced HIV prevalence predictions. Due to this uncertainty, we recommend basing population-based estimates on the range of outcomes, particularly when assessing the impact of interventions.
KeywordsMeasurement Methodological issues Mathematical modelling Sexual behaviour Sexual partners Female sex workers India
KND is supported by a post-doctoral research fellowship from the Canadian Institutes of Health Research and the Michael Smith Foundation for Health Research. Support for this study was provided by the Bill and Melinda Gates Foundation. The views expressed herein are those of the authors and do not necessarily reflect the official policy or position of the Bill and Melinda Gates Foundation.
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