antiretroviral treatment cohort analysis using time-updated cd4 counts assessment of bias with different analytic methods抗逆转录病毒治疗断代分析使用time-updated cd4计数偏差不同分析方法的评估.pdfVIP

Antiretroviral Treatment Cohort Analysis Using Time- Updated CD4 Counts: Assessment of Bias with Different Analytic Methods 1,2 3,4 3 3 1,2 Katharina Kranzer *, James J. Lewis , Richard G. White , Judith R. Glynn , Stephen D. Lawn , Keren Middelkoop2,5, Linda-Gail Bekker2,5, Robin Wood2,5 1 Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom, 2 The Desmond Tutu HIV Centre, Institute for Infectious Disease and Molecular Medicine, Faculty of Health Science, University of Cape Town, Cape Town, South Africa, 3 Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom, 4 Aurum Institute for Health Research, Johannesburg, South Africa, 5 Department of Medicine, Faculty of Health Science, University of Cape Town, Cape Town, South Africa Abstract Background: Survival analysis using time-updated CD4+ counts during antiretroviral therapy is frequently employed to determine risk of clinical events. The time-point when the CD4+ count is assumed to change potentially biases effect estimates but methods used to estimate this are infrequently reported. Methods: This study examined the effect of three different estimation methods: assuming i) a constant CD4+ count from date of measurement until the date of next measurement, ii) a constant CD4+ count from the midpoint of the preceding interval until the midpoint of the subsequent interval and iii) a linear interpolation between consecutive CD4+ measurements to prov