Xianhong Xie

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OBJECTIVE The objective of the study was to estimate the impact of human immunodeficiency virus (HIV) infection on the incidence of high-grade cervical intraepithelial neoplasia (CIN). STUDY DESIGN HIV-seropositive and comparison seronegative women enrolled in a prospective US cohort study were followed up with semiannual Papanicolaou testing, with(More)
Longitudinal measurement of biomarkers is important in determining risk factors for binary endpoints such as infection or disease. However, biomarkers are subject to measurement error, and some are also subject to left-censoring due to a lower limit of detection. Statistical methods to address these issues are few. We herein propose a generalized linear(More)
OBJECTIVE To describe the natural history of genital warts and vulvar intraepithelial neoplasia (VIN) in women with human immunodeficiency virus (HIV). METHODS A cohort of 2,791 HIV-infected and 953 uninfected women followed for up to 13 years had genital examinations at 6-month intervals with biopsy for lesions suspicious for VIN. RESULTS The(More)
BACKGROUND Case-cohort studies have become common in epidemiological studies of rare disease, with Cox regression models the principal method used in their analysis. However, no appropriate procedures to assess the assumption of proportional hazards of case-cohort Cox models have been proposed. METHODS We extended the correlation test based on Schoenfeld(More)
OBJECTIVE To estimate the effects of infection by HIV on the type-specific cumulative detection of cervicovaginal infection by human papillomavirus (HPV). DESIGN Retrospective assessment of prospectively collected data in a multicenter US cohort. METHODS HIV-seropositive and at-risk seronegative participants in the Women's Interagency HIV Study were(More)
OBJECTIVE To estimate the prevalence, incidence, and clearance of abnormal vaginal cytology and vaginal intraepithelial neoplasia (VAIN) in human immunodeficiency virus (HIV)-seropositive women. METHODS Pap tests were done semiannually for 335 HIV-seropositive and 75 HIV-seronegative women with prior hysterectomy in the prospective Women's Interagency HIV(More)
OBJECTIVE To estimate the frequency and histologic correlates of glandular abnormalities in cervical cytology among women with the human immunodeficiency virus (HIV) and to compare findings with those of women without HIV. METHODS In a cohort study of HIV-infected and uninfected women followed between 1994 and 2007, Pap tests were obtained every 6 months.(More)
CONTEXT US cervical cancer screening guidelines for human immunodeficiency virus (HIV)-uninfected women 30 years or older have recently been revised, increasing the suggested interval between Papanicolaou (Pap) tests from 3 years to 5 years among those with normal cervical cytology (Pap test) results who test negative for oncogenic human papillomavirus(More)
BACKGROUND Hepatitis C virus (HCV) viremia is thought to have broad systemic effects on the cellular immune system that go beyond its impact on just those T cells that are HCV specific. However, previous studies of chronic HCV and circulating T-cell subsets (activation and differentiation phenotypes) in HIV negatives used general population controls, rather(More)
There are several statistical methods for time-to-event analysis, among which is the Cox proportional hazards model that is most commonly used. However, when the absolute change in risk, instead of the risk ratio, is of primary interest or when the proportional hazard assumption for the Cox proportional hazards model is violated, an additive hazard(More)