Baseline antiretroviral drug resistance and clinical outcomes in an urban HIV clinic in Charlotte, North Carolina

Purpose: To assess the prevalence of transmitted drug resistance mutations (TDRMs) in HIV-infected treatment-naïve patients in our clinic.

Methods: The primary endpoint was the prevalence of TDRMs 2008-2011. Antiretroviral (ARV) drug susceptibility was retrospectively analyzed in treatment-naïve patients 2008-2011. Resistance was defined on the basis of the International AIDS Society 2011 definition and the 2009 CDC surveillance mutation list. Secondary endpoints included TDRM rates in recently diagnosed patients (HIV diagnosis in the last 12 months), predictors of persistence with care (12 months of follow-up data available) in patients who were initiated on ARVs 2008-2010, and virologic success (HIV-1 RNA <50 copies/mL after 12 months of therapy). Descriptive statistics, Pearson’s chi-square analysis, and logistic regression were used to analyze results.

Results: Among 189 treatment-naïve patients who entered care 2008-2011 (69% male, 87% African American, median CD4 count 299 cells/mm³), 19 (10%) had >1 TDRM. Year-to-year comparisons indicated a 0% TDRM rate in 2008, 12% in 2009, 8% in 2010, and 16% in 2011 (p=0.36). Among 137 recently diagnosed patients, TDRM rates were 0% in 2008, 13% in 2009, 10% in 2010, and 20% in 2011 (p=0.49). NNRTI resistance was most common (14/19; 74%), followed by NRTI (5/19; 26%); no PI TDRMs were noted. Of the 137 patients initiated on HAART; 103 (75%) demonstrated persistence in care and 81 (59%) achieved virologic success. Recent HIV diagnosis was the only factor significantly associated with persistence with care (OR 3.53; 95% CI 1.49 to 8.36; p=0.004) and with achieving HIV-1 RNA <50 copies/mL (OR 3.78; 95% CI 1.68 to 8.53; p=0.001). Counseling by a HIV clinical pharmacist was not associated with persistence in care or virologic success.

Conclusion: The prevalence of TDRMs in our clinic mirrors national surveillance data (15-19%). Efforts must be focused on improving patient retention and virologic success rates in urban HIV clinics.