Medium-term probability of success of antiretroviral treatment after early warning signs of treatment failure in West African adults

Abstract

West African adults with warning signs of failure of antiretroviral treatment (ART) at 6 months were assessed for the probability and factors associated with success at 36 months. After 6 months on ART, patients were included if they had a bad immunologic response (BIR) (month 6 CD4 count < pre-ART CD4 count + 50/mm(3)), incomplete virologic suppression (IVS) (month 6 plasma HIV-1 RNA >300 copies/ml), or both (Dual). They were followed for 30 months after inclusion. CD4 counts and HIV-1 RNA were measured every 3 months. We estimated the probability of reaching immunovirologic success (CD4 count >350/mm(3) and plasma HIV-1 RNA <300 copies/ml) and looked for determinants using Cox analysis. A total of 208 adults were included. Among patients in the IVS and Dual groups, 23% and 38% had at least one genotypic resistance mutation at month 6. The 36-month cumulative probability of immunovirologic success was 0.84 in BIR, 0.81 in IVS, and 0.67 in Dual (p = 0.02). Adjusting for CD4 count, viral load, ART regimen, and morbidity, patients who had no genotypic resistance mutations at month 6 or a medication possession ratio (MPR) >90% between month 6 and month 36 had a likelihood of success 3.8 and 3.6 higher than other patients. The 36-month probability of success was 0.56 and 0.86 in patients with an MPR <90% and >90% and 0.59 and 0.84 in patients with and without resistance. After warning signs of failure at 6 months, a large proportion of patients reaches immunovirologic success before 36 months provided there is a high rate of adherence to medication and the absence of early resistance mutations.