The influence of antiretroviral-resistance tests on treatment effectiveness in patients with HIV and virological failure

The objective of this study is to determine the influence of antiretroviral-resistance tests on the suppression of HIV (< 400 copies/mL) in patients with virological failure who require an alternative antiretroviral treatment. A retrospective observational study on cohorts of adult patients. Two groups were defined: cases in which the prescription of antiretrovirals was based on resistance tests (group A), and controls in which no such test was performed (group B). Each group was divided into two sub-groups according to the number of changes in treatment: first treatment change (A1 and B1); a subsequent change (A2 and B2). The main variable was defined as the proportion of patients with negative viral load (< 400 copies/mL) at the third month of treatment; secondary variables were the proportion of patients with negative viral load at the sixth month and an average variation in the CD4 level at the third and sixth months after this change. A total of 152 patients were included in this study, 59 in group A and 93 in group B (control). No differences were found in the stage of the disease at the time of administering an alternative treatment. 59.3% of the patients in group A and 47.3% of the patients in group B had suppressed the HIV viral load at the third month, although this difference was not statistically significant (p = 0.149). No statistically significant differences were found in the secondary variables. The use of antiretroviral-resistance tests increased effectiveness in the response to the selected antiretroviral treatment in the study group, although we did not obtain significant differences for the group of patients in which these tests were not performed.