aidsCT {icensBKL}

AIDS Clinical Trial ACTG 181

Description

AIDS Clinical Trials Group protocol ACTG 181 was a natural history substudy of a comparative trial of three anti-pneumocystis drugs. Patients were followed for shedding of cytomegalovirus (CMV) in urine and blood samples, and for colonization of mycobacterium avium complex (MAC) in the sputum and stool. Subjects were screened for CMV in the urine every 4 weeks and in the blood every 12 weeks. Subjects were screened for MAC every 12 weeks. Many patients missed several of the prescheduled clinic visits, and returned with new laboratory indications for CMV or MAC. Thus, their times until first CMV shedding or MAC colonization are censored into intervals of time when the missed clinic visits occurred. However, for the current analysis, visit times were rounded to the closest quarter because they are of practical interest to physicians in that they correspond to standard clinic schedules. Only 204 of the 232 subjects in the study who were tested for CMV shedding and MAC colonization at least once during the trial, and did not have a prior CMV or MAC diagnosis are included in the data base.

Usage

data(aidsCT)

Format

a data frame with 204 rows and the following variables

L.CMV

left (lower) limit of interval (L.CMV, R.CMV] that contains time of CMV shedding (months). It is NA if the time of CMV shedding is left-censored at R.CMV.

R.CMV

right (upper) limit of interval (L.CMV, R.CMV] that contains time of CMV shedding (months). It is NA if the time of CMV shedding is right-censored at L.CMV.

L.MAC

left (lower) limit of interval (L.MAC, R.MAC] that contains time of MAC colonization (months). It is NA if the time of MAC colonization is left-censored at R.MAC.

R.MAC

right (upper) limit of interval (L.MAC, R.MAC] that contains time of MAC colonization (months). It is NA if the time of MAC colonization is right-censored at L.MAC.

Source

Betensky, R. A. and Finkelstein, D. M. (1999). A non-parametric maximum likelihood estimator for bivariate interval censored data. Statistics in Medicine, 18, 3089-3100.

Examples

data("aidsCT", package="icensBKL")
summary(aidsCT)