Abstract: _Virological failure was observed in patients with phenotypic resistance to efavirenz (67 vs. 11%; relative risk [RR], 4; 95% confidence interval [CI], 1.07-14.89; p = 0.04), or in presence of the
K103N mutation (52 vs. 17%; RR, 1.77; 95% CI, 1.12-2.79; p = 0.02), and these results remained unchanged after adjusting for HIV load, or by resistance to the accompanying drugs in the salvage regimen.