Implementation and operational research: correlates of adherence and treatment failure among Kenyan patients on long-term highly active antiretroviral therapy

Background:Universal access to highly active antiretroviral therapy (HAART) is still elusive in most developing nations. We asked whether peer support influenced adherence and treatment outcome and if a single viral load (VL) could define treatment failure in a resource-limited setting. Methods: A multi-center longitudinal and cross-sectional survey of VL CD4 T-cells and adherence in 546 patients receiving HAART for up to 228 months. VL and CD4 counts were determined using m2000 Abbott RealTime HIV-1 assay and FACS respectively. Adherence was assessed based on pill-count and on self-report. Results: Respectively 55.8% 22.2% and 22% of the patients had good fair and poor adherence. Adherence peer support and regimen but not HIV disclosure age or gender independently correlated with VL and durability of treatment in a multivariate analysis (p<0.001). Treatment failure was 35.9% using sequential VL but ranged between 27% and 35% using alternate single VL cross-sectional definitions. More patients failed stavudine (41.2%) than zidovudine (37.4%) or tenofovir (28.8% P=0.043) treatment arms. Peer support correlated positively with adherence (c2 p<0.001) with non-adherence highest in the stavudine arm. VL before the time of regimen switch was comparable between patients switching and those not switching treatment. Moreover 36% of those switching still failed second-line regimen. Conclusion: Weak adherence support and inaccessible VL testing threaten to compromise the success of HAART scale-up in Kenya. To hasten ART monitoring and decision-making we suggest strengthening patient-focused adherence programs optimizing and aligning regimen to WHO standards and a single point-of-care VL testing when multiple tests are unavailable.