Validity of clinical and immunological monitoring to detect virological failure in HIV infected children on antiretroviral therapy in Dar es salaam, Tanzania.

Abstract

Background: Globally, it is estimated that 2 million children under the age of 15 years are living with human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) and the majority reside in sub-Saharan Africa, South and Southeast Asia. In Tanzania, it is estimated that around 160,000 children are living with HIV and more than 11,000 children are on antiretroviral therapy (ART). The treatments response monitoring is primarily by using clinical and immunological parameters to detect virological failure. The validity of clinical and immunological monitoring to detect virological failure in children receiving ART is not well documented. Objective: To determine the validity of clinical and immunologic monitoring in detecting virological failure among HIV infected children on ART in Dar es Salaam. Methods: The study is health facility based cross sectional study of HIV infected children attending care and treatment clinics, who were receiving ART for at least six months. We screened 485 children on ART in Dar es Salaam for enrollment. 218 met inclusion criteria and blood samples were taken for viral load (VL) testing. Two hundreds and seventeen results were available for analysis. One VL results was inconclusive. The viral load testing was performed using Roche Cobas Amplicor HIV-1 RNA monitor version 1.5 assay (Roche Diagnostics, USA). Plasma VL below 400 copies/ml indicates good response to ART while Plasma VL ≥401 copies/ml defined Virological failure. SPSS version 17.0 and Epi Info Version 6.0. (CDC, Atlanta, USA) were used for statistical analysis. Chi square test was used to analyse categorical variables. Logistic regression was used to determine predictor of virological failure. Results: Two hundred and eighteen children were included in the study. Overall mean age of the children was 10.6 years (range 1-16 years). Of 217 children with available viral load results, 124 (57.1%) had virological failure. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of clinical criteria were 12.9%, 90.3%, vii 64.0% and 43.8% respectively. The immunological criteria had sensitivity, specificity PPV and NPV of 22.6%, 73.1%, were 53.3% and 41.4% respectively. The combined clinical and immunological criteria has sensitivity of 25.8%, specificity 69.9%, while PPV and NVP were 53.3% and 41.4% respectively. Children who received NVP based regimens were more likely to have virological failure compared to other regimens, OR=2, 95% CI (1.20-3.64), p=0.03. Conclusion: Virological failure was highest followed by immunological and clinical failures. This study demonstrated a poor performance of current recommended clinical and immunological criteria to monitor HIV-infected children on ART. Children who were on NVP-based regimens had a higher risk of developing virological failure than those who were in other regimens. Recommendations: Improving access to viral load testing is feasible approach at this stage for early and reliable identification of virological failure in children on ART in order to make informed decision on switching to second line regimen. Regular surveillance on resistance test is recommended to detect early emergence of HIV drug resistance