%0 Journal Article
%T Effect of misclassification of antiretroviral treatment status on the prevalence of transmitted HIV-1 drug resistance
%A Hannah Castro
%A Deenan Pillay
%A Caroline Sabin
%A David T Dunn
%A the UK Collaborative Group on HIV Drug Resistance
%J BMC Medical Research Methodology
%D 2012
%I BioMed Central
%R 10.1186/1471-2288-12-30
%X The impact of misclassification bias on the rate of TDR was examined. We developed methods to obtain adjusted estimates of the prevalence of TDR for different misclassification rates, and conducted sensitivity analyses of trends in the prevalence of TDR over time using data from the UK HIV Drug Resistance Database. Logistic regression was used to examine trends in the prevalence of TDR over time.The observed rate of TDR was higher than true TDR when misclassification was present and increased as the proportion of misclassification increased. As the number of na£żve patients with a resistance test relative to the number of experienced patients with a test increased, the difference between true and observed TDR decreased. The observed prevalence of TDR in the UK reached a peak of 11.3% in 2002 (odds of TDR increased by 1.10 (95% CI 1.02, 1.19, p(linear trend) = 0.02) per year 1997-2002) before decreasing to 7.0% in 2007 (odds of TDR decreased by 0.90 (95% CI 0.87, 0.94, p(linear trend) < 0.001) per year 2002-2007. Trends in adjusted TDR were altered as the misclassification rate increased; the significant downward trend between 2002-2007 was lost when the misclassification increased to over 4%.The effect of misclassification of ART on estimates of the prevalence of TDR may be appreciable, and depends on the number of na£żve tests relative to the number of experienced tests. Researchers can examine the effect of ART misclassification on their estimates of the prevalence of TDR if such a bias is suspected.Estimates of the prevalence of transmitted HIV drug resistance (TDR) in a population are derived from resistance tests performed on samples from patients thought to be na£żve to antiretroviral treatment (ART). The certainty of whether a patient is na£żve to treatment at the time a sample for resistance testing is taken relies on sources of information about a patient's treatment status. Patients who have moved countries or clinical centres may not remember the exact date o
%U http://www.biomedcentral.com/1471-2288/12/30