Risk factors of virologic failure and slow response to art among HIV-infected children and adolescents in Nairobi

Background : Antiretroviral therapy (ART) in resource-limited settings is effective when backed up with adequate clinical, immunological, and virologic monitoring. Undetected, virologic failure results in increased HIV-1 drug resistance mutations (DRMs), morbidity and mortality, or the need for costly second-line and third-line ART. Objective : To evaluate the prevalence, patterns, and risk factors of virologic failure and slow response to ART, among children and adolescents in resource-limited settings in Nairobi, Kenya. Design : A Retrospective study. Setting : The 8 Lea Toto Programme (LTP) Clinics in Dagoretti, Dandora, Kangemi, Kariobangi, Kawangware, Kibera, Mukuru, and Zimmerman areas of Nairobi. Subjects: One hundred and forty-six HIV-infected children and adolescents aged 1 month to 19 years of the LTP in Nairobi Kenya. Medical and demographic data including, HIV-1 viral loads, information on adherence to ART, HIV-1 DRMs and other key determinants of virologic failure, collected over a period of 2 years, was used for this study. Results : A threshold of 1,000 HIV RNA copies/ml was used to determine treatment outcome. The virologic failure rates in this cohort were 43.8% after 6 months, 32.2% after 12 months, 28.8% after 18 months, and 24.0% after 24 months of first-line ART. Twelve (8.2%) of 146 children showed a slow response to ART: they initially failed ART at 12 months, but had treatment success after 18 to 24 months. The rates of virologic rebound were 4 (2.7%) after 18 months and 3 (2.1%) after 24 months of ART. Multivariate Cox proportional hazards regression revealed that children with suboptimal adherence to ART were 37 times more likely to experience virologic failure (P = 0.000003). Conclusions : This study showed that ART implementation in resource-limited settings is effective when regular virologic monitoring, adherence counselling, and HIV-DR testing are available. Secondly, adherence to ART is a strong predictor of treatment outcome for children and adolescents in resourcelimited settings. Therefore, methods of optimizing adherence levels should be explored and implemented.