Background: To investigate the reasons and risk factors for modification of the first combined antiretroviral therapy (cART) currently used for HIV infected patients who were treatment naïve in Shanghai China.
Methods: Making a retrospective observational research on treatment naïve patients with HIV infection who initiated cART during the period of September 1st 2005---December 1st 2013. The demographic and clinical data were collected from the first visit to the time of the first regimen modification or the last visit in December 1st, 2014. The reasons of treatment modification were recorded. Survival analysis of modification was made by Kaplan-Meier curves analysis and log rank test, and a Cox multiple regression model was constructed to identify related factors of modification.
Results: A total number of the eligible participants were 3372 and 871(25.8%) patients changed their first cART regimen. The median follow up was 22 months [interquartile range (IQR) 14-39]. Among patients who modified the original regimen, drug toxicity occurred in 805(92.4%) participants and 44(5.1%) experienced treatment failure. In multiple regression analysis regimen modification was associated with patients' age more than 40 years old (aHR 1.224, 95%CI 1.051-1.426, P = 0.010), CD4 less than 200(aHR 1.218, 95%CI 1.044-1.421, P = 0.012) and the initial regimen they received. Compared with the regimen of TDF+3TC+EFV, patients with regimen of d4T+3TC+NVP, d4T+3TC+EFV, AZT+3TC+NVP or AZT+3TC+EFV were 10.4, 8.2, 6.4, 2.5 times more likely to modify their initial regimen, respectively.
Conclusions: The main reason for the regimen switch was drug toxicity and main risk factors for regimen modification were age older than 40 years, CD4 cell counts less than 200 at baseline and regimen they received. Among the 2NRTI plus 1NNRTI regimens, the co-formulation of d4T+3TC+NVP had the highest risk for modification while the regimen of TDF+3TC+EFV was the most tolerable treatment regimen in first years' follow up.