The effect of covariates on the induction time of AIDS using improved imputation of exact seroconversion times.
This paper explores the effects of covariates such as age, gender, chronological time of seroconversion, and mode of virus transmission on the interval between HIV seroconversion and the development of AIDS. For many cohorts which are available to provide information about such effects, both the time of seroconversion and the time of onset of AIDS may be right- or interval-censored. To analyse these doubly-censored data, we propose a method in which we first estimate the marginal distribution of the chronological time of seroconversion and use this distribution to impute the seroconversion time for each subject. Subsequently, we estimate the distribution of induction times conditional on the seroconversion distribution. We apply this technique to a cohort of HIV seropositive subjects recruited from various outpatient facilities throughout Italy and show that age at seroconversion has the greatest effect on induction time.
Harvard School of Public Health, Department of Biostatistics, Boston, Massachusetts 02115.
K
K
Gauvreau
V
V
Degruttola
M
M
Pagano
R
R
Bellocco
D000163:Acquired Immunodeficiency Syndrome / Q000453:epidemiology*; D000328:Adult; D017668:Age of Onset; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000175:diagnosis / Q000453:epidemiology / Q000635:transmission; D006679:HIV Seropositivity / Q000453:epidemiology*; D006716:Homosexuality; D006801:Humans; D007558:Italy / Q000453:epidemiology; D016013:Likelihood Functions; D008297:Male; D008954:Models, Biological; D011159:Population Surveillance / Q000379:methods*; D012737:Sex Factors; D012725:Sexual Behavior; D015819:Substance Abuse, Intravenous; D013997:Time Factors