STUDY LIMITATIONS
The data of this study extracted from the normal medical record which
can veritably reflect the outcome of the current second-line ART
management. As a retrospective study, selection bias was possibly
introduced because of the fact that patients with incomplete records
would be excluded. Some important variables associated with mortality
like the viral load and body mass index when switch to second-line ART
which were not recorded for most of the patients. Adherence of ART was
confirmed variable don’t record in the normal medical record.