Diagnosis of antiretroviral therapy failure in Malawi: poor performance of clinical and immunological WHO criteria.

Objectives: In antiretroviral therapy (ART) scale-up programmes in sub-Saharan Africa viral load monitoring is not recommended. We wanted to study the impact of only using clinical and immunological monitoring on the diagnosis of virological ART failure under routine circumstances.

Methods: Clinicians in two urban ART clinics in Malawi used clinical and immunological monitoring to identify adult patients for switching to second-line ART. If patients met clinical and/or immunological failure criteria of WHO guidelines and had a viral load <400 copies/ml there was misclassification of virological ART failure.

Results: Between January 2006 and July 2007, we identified 155 patients with WHO criteria for immunological and/or clinical failure. Virological ART failure had been misclassified in 66 (43%) patients. Misclassification was significantly higher in patients meeting clinical failure criteria (57%) than in those with immunological criteria (30%). On multivariate analysis, misclassification was associated with being on ART <2 years [OR = 7.42 (2.63, 20.95)] and CD4 > 200 cells/microl [OR = 5.03 (2.05, 12.34)]. Active tuberculosis and Kaposi's sarcoma were the most common conditions causing misclassification of virological ART failure.

Conclusion: Misclassification of virological ART failure occurs frequently using WHO clinical and immunological criteria of ART failure for poor settings. A viral load test confirming virological ART failure is therefore advised to avoid unnecessary switching to second-line regimens.