Prior antiretroviral therapy experience protects against zidovudine-related anaemia

Objective We investigated the use of antiretroviral therapy regimens containing zidovudine or stavudine, using data from the TREAT Asia HIV Observational Database (TAHOD), a multicentre, prospective, observational study of an HIV-infected cohort in the Asia-Pacific Region. Methods A proportional hazards regression analysis of factors associated with the time to discontinuation of initial regimens containing zidovudine or stavudine and a logistic regression analysis to identify factors associated with a diagnosis of anaemia within 6 months of commencement of zidovudine in initial or subsequent regimens were performed. Results Patients who started zidovudine were more likely to stop within the first 9 months of treatment than those who started on stavudine; the reverse was true after 9 months. Anaemia (haemoglobin <= 10 g/dL) occurred in the first 6 months in 57 of 433 patients (13%) on zidovudine. Baseline anaemia was the strongest predictive factor for subsequent anaemia, and prior antiretroviral therapy (ART) experience was protective for development of anaemia. Conclusions These data support baseline haemoglobin testing and avoidance of zidovudine if the patient is anaemic. The protective effect of prior ART for development of anaemia on zidovudine supports the short-term safety of a stavudine to zidovudine switch with routine haemoglobin monitoring in this cohort. Further studies in resource-poor settings of longer term efficacy and toxicities of ART switch strategies are needed.