We conducted retrospective analysis using routinely available program data. Study included adult (age ≥18 years) HIV-infected patients enrolled in national HIV/AIDS treatment and care program. Patients with confirmed HIV drug resistance, who were switched to second-line ART regimens from August 2005 to December 2010 were included in the analysis. Patients were followed until July 1, 2011.
Georgia’s national HIV/AIDS treatment and care program provides HIV related medical services to all diagnosed HIV patients. The program is coordinated by the Infectious Diseases, AIDS and Clinical Immunology Research Center (IDACIRC), which is country’s referral institution for HIV diagnosis, treatment and care. Patients receive services at IDACIRC clinic and three dedicated regional facilities.
Provision of ART in Georgia is governed by national HIV/AIDS treatment and care guidelines, which was first developed in 2004. During the study period (2005–2010) ART was recommended at CD4 count ≤200 cells/mm3. The recommended initial regimen consisted of two nucleoside reverse transcriptase inhibitors (NRTI) and one non-nucleoside reverse transcriptase inhibitor (NNRTI). Zidvudine (AZT) + lamivudine (3TC) has been preferred NRTI component since 2004. Stavudine (d4T) was phased out after 2007 revision of national guidelines, and was replaced by abacavir (ABC) + lamivudine (3TC) or tenofovir (TDF) + emtricitabine (FTC). Efavirenz (EFV) has been the preferred NNRTI with nevirapine (NVP) being recommended as an alternative to EFV.
According to national guidelines follow-up of patients on ART relied on regular monitoring of CD4 count and HIV viral load. HIV drug resistance was performed routinely among patients with virologic failure, defined as confirmed plasma HIV RNA >400 copies/ml 6 months after starting therapy or after undetectable viral load while on therapy. Results of drug résistance testing were used for selection of second-line therapy.
During the study period plasma HIV RNA levels were measured using either Amplicor HIV-1 Monitor test, version 1.5 (Roche Molecular Diagnostics, Germany) or the real-time PCR assay COBAS TaqMan HIV-1 test (Roche Molecular Diagnostics, Germany). For genotypic resistance testing the TruGene HIV-1 Genotyping Kit was employed according to the manufacturer’s instructions using OpenGene DNA Sequencing System (Siemens Medical Solutions Diagnostics, Germany). The Stanford University algorithm (http://hivdb.stanford.edu/) were used for resistance interpretation.
Demographic, epidemiological, clinical and laboratory data were extracted from program and medical records. Baseline characteristics were collected at the time point when patient experienced virologic failure. Adherence was expressed as percentage based on medication refill data, and was calculated as days supply of medications dispensed divided by days between prescription fills. The primary outcome was proportion of patients achieving viral suppression (<400 copies/ml) after the switch to second line ART. Predictors of primary outcome were assessed in modified Poisson regression analysis . All statistical analyses were performed using SAS 9.2.
Study was approved by the Institutional Review Board of IDACIRC.