Predictors of treatment failure in Western Cape, South Africa

Polly Clayden, HIV i-Base

In an oral abstract, Mohammed Ishaaq Datay presented findings from a preliminary analysis of predictors of treatment failure in patients receiving HAART in rollout cohorts in Western Cape Province, South Africa. Investigators from the University of Oxford and the University of Cape Town conducted the study.

As of June 2006, over 18,000 patients from 44 clinics were receiving HAART in this province. Approximately 1.5% experienced treatment failure (defined as two viral load results >1000 copies/mL and a switch to second line HAART).

This was a retrospective case control study. The control group maintained viral load <400 copies/mL at time of case failure and continued on first line HAART. The two groups were matched for treatment duration and clinic attended.

The investigators sampled 368 eligible patient records (130 cases and 238 controls) from eight clinics (representing 9249 patients receiving care). Of the 238 controls, 174 (73%) had a baseline CD4 count of less than 150 cells/mm3.

In the multivariate analysis, the predictors of failure were: low baseline CD4 <150 cells/mm3 (OR 3.2, 95%CI 1.5-6.9), previous antiretrovirals for MTCT (OR 3.0, 95%CI 1.4-6.3); treatment interruptions (OR 3.7, 95%CI 2.2-6.4) and nevirapine-based HAART (OR 2.0, 95%CI 1.2-3.5).

The investigators found that treatment interruptions were strongly associated with travel/migration p=0.001; 48/78 (62%) of treatment interruptions were due to defaulting (lost to follow-up?); 29/48 (60%) of defaulters travelled and 21/29(72%) of travelling was to Eastern Cape Province.

They also reported that prior use of MTCT drugs within 12 months of starting HAART and the use of NVP as the MTCT drug were more strongly associated with treatment failure.

They concluded: “The high prevalence of a very low baseline CD4 is concerning in light of its association with failure. Our study adds insight into the role of treatment interruption, choice of NNRTI and MTCT exposure. Further study of treatment interruption and travel is needed working towards intervention”.


Datay MI, Boulle A, Yudkin P et al. Predictors of virological treatment failure in the HIV roll-out cohorts of the Western Cape Province, South Africa. 14th Annual BHIVA Conference, Dublin, 2008. HIV Medicine, 9 (Suppl. 1). Oral Abstract 013.

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