The association of HIV susceptibility testing with survival among HIV-infected patients receiving antiretroviral therapy: a cohort study.

BACKGROUND

HIV-1 genotypic and phenotypic susceptibility testing (GPT) optimizes antiretroviral selection, but its effect on survival is unknown.

OBJECTIVE

To evaluate the association between GPT and survival.

DESIGN

Cohort study.

SETTING

10 U.S. HIV clinics.

PATIENTS

2699 HIV-infected patients eligible for GPT (plasma HIV RNA level >1000 copies/mL) seen from 1999 through 2005.

MEASUREMENTS

Demographic characteristics, clinical factors, GPT use, all-cause mortality, and crude and adjusted hazard ratios (HRs) for the association of GPT with survival.

RESULTS

Patients were followed for a median of 3.3 years; 915 (34%) had GPT. Patients who had GPT had lower mortality rates than those who did not (2.0 vs. 2.7 deaths per 100 person-years). In standard Cox models, GPT was associated with improved survival (adjusted HR, 0.69 [95% CI, 0.51 to 0.94]; P = 0.017) after controlling for demographic characteristics, CD4+ cell count, HIV RNA level, and intensity of clinical follow-up. In subgroup analyses, GPT was associated with improved survival for the 2107 highly active antiretroviral therapy (HAART)-experienced patients (2.2 vs. 3.2 deaths per 100 person-years for patients who had GPT vs. those who did not have GPT; adjusted HR, 0.60 [CI, 0.43 to 0.82]; P = 0.002) and for the 921 triple antiretroviral class-experienced patients (2.1 vs. 3.1 deaths per 100 person-years; adjusted HR, 0.61 [CI 0.40 to 0.93]; P = 0.022). Marginal structural models supported associations between GPT and improved survival in the overall cohort (adjusted HR, 0.54; P = 0.001) and in the HAART-experienced group (adjusted HR, 0.56; P = 0.003).

LIMITATIONS

Use of GPT was not randomized. Residual confounding may exist.

CONCLUSION

Use of GPT was independently associated with improved survival among HAART-experienced patients.

PRIMARY FUNDING SOURCE

Centers for Disease Control and Prevention.