Objectives
Zidovudine (AZT) is recommended for first-line antiretroviral therapy (ART) in resource limited settings. AZT may, however, lead to anemia and impaired immunological response. We compared CD4 counts over 5 years between patients starting ART with and without AZT in Southern Africa.
Design
Cohort study
Methods
Patients aged ≥16 years who started first-line ART in South Africa, Botswana, Zambia or Lesotho were included. We used linear mixed-effect models to compare CD4 cell count trajectories between patients on AZT-containing regimens and patients on other regimens, censoring follow-up at first treatment change. Impaired immunological recovery, defined as a CD4 count below 100 cells/μl at 1 year, was assessed in logistic regression. Analyses were adjusted for baseline CD4 count and haemoglobin level, age, gender, type of regimen, viral load monitoring and calendar year.
Results
72,597 patients starting ART, including 19,758 (27.2%) on AZT, were analysed. Patients on AZT had higher CD4 cell counts (150 vs.128 cells/μl) and haemoglobin level (12.0 vs. 11.0 g/dl) at baseline, and were less likely to be female than those on other regimens. Adjusted differences in CD4 counts between regimens containing and not containing AZT were −16 cells/μl (95% CI −18 to −14) at 1 year and −56 cells/μl (95% CI −59 to −52) at 5 years. Impaired immunological recovery was more likely with AZT compared to other regimens (odds ratio 1.40, 95% CI 1.22–1.61).
Conclusions
In Southern Africa AZT is associated with inferior immunological recovery compared to other backbones. Replacing AZT with another NRTI could avoid unnecessary switches to second-line ART.