[Factors associated with resistance to human immunodeficiency virus protease inhibitors].

Background: To assess the risk factors associated with genotypic resistance to protease inhibitors (PI) in HIV-infected subjects with virologic failure despite highly active antiretroviral treatment (HAART).

Patients And Method: Retrospective chart review including 47 consecutive patients with virologic failure despite PI-based HAART who had undergone a genotypic HIV-1 testing. The prevalence of genotypic resistance to PI was determined and several demographic, clinical and laboratory variables were compared between patients with and without genotypic resistance to those drugs.

Results: The entire nucleotide sequence of the protease gene was obtained in 43 of the 47 patients; 18 of them had genotypic resistance to PI. Genotypic resistance to PI was associated with a previous therapy with suboptimal antiretroviral regimens (OR = 10.2; 95% CI, 1.05-245.1; P = 0.02), duration of antiretroviral therapy longer than 18 months (OR = 13.3; 95% CI, 1.23-340.85; P = 0.01), greater number of antiretroviral regimens and drugs before the virologic failure (p < 0.01) and presence of the 184V mutation in the reverse transcriptase gene (OR = 5.6; 95% CI, 1.2-29.2; P = 0.02). There was no relationship between PI resistance and the risk group, viral load or CD4 cell count. In the multivariate analysis, previous therapy with suboptimal antiretroviral regimens was the better predictor of PI resistance (OR = 11.1; 95% CI, 1.04-117.47; P = 0.046).

Conclusions: Patients treated with suboptimal antiretroviral activity regimens before starting HAART can be at greater risk of developing genotypic resistance to protease inhibitors.