Long-Term Effectiveness of First-Line Antiretroviral Theraphy in a Cohort of HIV-1 Infected Patients

Background: Eligibility criteria might explain differences in viral response to combined antiretroviral treatment (cART) between clinical trials and routine care setting. Our aim was to assess the effectiveness of cART and factors associated to therapeutic failure (TF) in real clinical conditions. Methods: A prospective cohort analysis including HIV-1 infected patients who started a cART between January 2004 and December 2009, at Vall d’Hebron Hospital. Effectiveness was evaluated as time to TF defined as the first of either virologic failure, treatment discontinuation whatever the reason other than switching, loss to follow-up, or death. The Kaplan-Meier method was used to estimate time-to-event distributions and Cox regression modelling to identify factors associated with TF. Results: We analyzed 232 patients; median CD4+ cell count was 229 cells/mm3 and median viral load 4.89 log10. Almost a third of patients was co-infected with HCV and/or HBV. Tenofovir plus lamivudine/emtricitabine (67%) was the commonest backbone, and efavirenz (77%) the preferred third drug. The proportion of patients with no TF at month 12, 24 and 36 was 82.9%, 78.5% and 76% respectively. TF occurred in 57 (24.6%) patients, mainly due to intolerance or toxicity. The risk of TF was higher in patients starting cART before 2006 and in those with a protease inhibitor based regimen. Conclusions: After a median follow-up of 36.5 months, three-fourth of patients who started first-line cART remained free of TF. Treatment discontinuation stands as the leading cause of TF.