BACKGROUND : The number of Human Immunodeficiency Virus (HIV) infected people eligible for initiation on
antiretroviral Therapy (ART) is increasing. ART programmatic success requires that patients who are taking ART
remain on treatment and are followed up regularly. This study investigated factors associated with being lost to
follow-up, in a cohort of patients enrolled in a pharmacovigilance study in South Africa.
METHODS : This was a retrospective observational cohort study performed at one of the Medunsa National
Pharmacovigilance Centre’s (MNPC) ART sentinel surveillance sites. Loss to Follow-up (LTFU) was defined as “a patient
who had been followed up at the sentinel site, who had not had contact with the health facility for 180 days or more
since their last recorded expected date of return or if there were 180 days or more between the expected date of
return and the next clinic visit”.
RESULTS : Out of 595 patients, 65.5 % (n = 390) were female and 23.4 % (n = 139) were LTFU. The median time
on ART before LTFU was 21.5 months (interquartile range: 12.9 – 34.7 months). The incidence rate of LTFU
was 103 per 1000 person-years in the first year on ART and increased to 405 per 1000 person-years in the
eighth year of taking ART. Factors associated with becoming LTFU included not having a committed partner
(Adjusted Hazard Ratio (aHR): 2.9, 95 % Confidence Interval (CI):1.19-6.97, p = 0.019), being self-employed (aHR: 13.9,
95 % CI:2.81 - 69.06, p = 0.001), baseline CD4 count > 200 cells/ml (aHR: 3.8, 95 % CI: 1.85-7.85, p < 0.001), detectable last
known Viral Load (VL) (aHR: 3.6, 95 % CI:1.98 - 6.52, p < 0.001) and a last known World Health Organisation clinical stage
three or four (aHR: 2.0, 95 % CI:1.22-3.27, p = 0.006). Patients that previously had an ART adverse event had a lower risk
(aHR: 0.6, 95 % CI: 0.38 - 0.99, p = 0.044) of becoming LTFU than those that had not.
CONCLUSION : The incidence rate of LTFU increases with additional years on ART. Intensified measures to improve
patient retention on ART must be prioritised with increasing patient time on ART and in patients that are at increased
risk of becoming lost to follow-up.