Background: Optimizing initial antiretroviral therapy (ART) regimens is of paramount
importance in improving the durability of treatment efficacy and patient prognosis. We
evaluated the reasons for and risk factors relating to ART modifications in an outpatient
cohort in Mbabane, Swaziland.
Methods: Retrospective cohort analysis of data for 782 patients who started first-line ART
between 1 March 2006 and 31 March 2008. Multivariate piecewise Cox regression models
were used to identify potential predictors of treatment modification.
Results: Over a median follow-up period of 21 months, 17.5% of patients modified their
regimen. Drug toxicity was the commonest reason (77 %) while drug contra-indications,
namely tuberculosis (13.1%) and pregnancy (6.6%) accounted for 20% of the modifications.
In the adjusted multivariate Cox piecewise regression model; after 11 months on ART,
baseline CD4 cell count < 200cells/mm3 (HR = 4.42; 95% CI: 1.62 – 12.1), having Stavudine
(d4T) in the initial regimen (HR = 2.64; 95% CI: 1.56 – 4.46) and baseline weight > 60kg (HR
= 2.40; 95% CI: 1.43 – 4.04) significantly increased the hazards for modification.
Conclusions: Initiating HAART at higher CD4 counts, avoiding drugs with poor safety
profiles, such as Stavudine (d4T), and identifying individuals who may require therapy for
tuberculosis or who may become pregnant could reduce modification rates.