Follow-up time was calculated from TB treatment initiation until the earliest of: last visit date for those who were LTFU, date of death, termination date or administrative censoring at 24 months. In the results published previously, 8 (link),14 (link),15 (link) administrative censoring took place at 18 months post TB treatment initiation but in this analysis administrative censoring was at 24 months. Analysis was conducted at different follow-up times namely: during TB treatment, after the completion of TB treatment, before and after ART initiation as well as at 24 months post TB treatment initiation.
Multivariate proportional hazards regression models were used to identify predictors of LTFU at different follow-up time points. Baseline variables that were included in the multivariate analysis were: trial arm, age, gender, WHO stage of HIV disease, CD4+ cell count, presence or absence of history of TB and employment status. We used Poisson approximations to calculate 95% confidence interval (CI) for incidence rates and incidence rate ratio (IRR). Proportionality was tested by fitting the time dependent covariates created by interacting the baseline variables and a function of survival time. Statistical analyses were done using Statistical Analysis Software version 9.3 (SAS Institute, Cary, North Carolina, USA).
Multivariate proportional hazards regression models were used to identify predictors of LTFU at different follow-up time points. Baseline variables that were included in the multivariate analysis were: trial arm, age, gender, WHO stage of HIV disease, CD4+ cell count, presence or absence of history of TB and employment status. We used Poisson approximations to calculate 95% confidence interval (CI) for incidence rates and incidence rate ratio (IRR). Proportionality was tested by fitting the time dependent covariates created by interacting the baseline variables and a function of survival time. Statistical analyses were done using Statistical Analysis Software version 9.3 (SAS Institute, Cary, North Carolina, USA).
