Regional differences in the risk of triple class failure in European patients starting combination antiretroviral therapy after 1 January 1999.

Regional differences across Europe in triple class failure (TCF; the failure of each of the three separate main classes of antiretrovirals (ARVs) with a viral load >1000 HIV-1 RNA copies/mL for >4 months) have not been described. A total of 1956 patients started combination ARV therapy after 1 January 1999, of whom 123 patients developed TCF [6.3%; incidence 16.7 per 1000 person-years of follow-up; 95% confidence interval (CI) 13.7-19.6]. After adjustment, patients from Eastern Europe had a significantly increased incidence of TCF compared with patients from Southern Europe/Argentina (3.05; 95% CI 1.36-6.82; P=0.0067) while patients taking either a boosted protease inhibitor regimen (0.33; 95% CI 0.15-0.74; P=0.0072) or a nonnucleotide reverse transcriptase inhibitor (NNRTI)-based regimen (0.59; 95% CI 0.37-0.94; P=0.026) had a reduced incidence of TCF.