Calendar Time Trends in the Incidence and Prevalence of Triple-Class Virologic Failure in Antiretroviral Drug-Experienced People With HIV in Europe

Background: Despite the increasing success of antiretroviral therapy (ART), virologic failure of the 3 original classes [triple-class virologic failure, (TCVF)] still develops in a small minority of patients who started therapy in the triple combination ART era. Trends in the incidence and prevalence of TCVF over calendar time have not been fully characterised in recent years. Methods: Calendar time trends in the incidence and prevalence of TCVF from 2000 to 2009 were assessed in patients who started ART from January 1, 1998, and were followed within the Collaboration of Observational HIV Epidemiological Research Europe (COHERE). Results: Of 91,764 patients followed for a median (interquartile range) of 4.1 (2.0-7.1) years, 2722 (3.0%) developed TCVF. The incidence of TCVF increased from 3.9 per 1000 person-years of follow-up [95% confidence interval (CI): 3.7 to 4.1] in 2000 to 8.8 per 1000 person-years of follow-up (95% CI: 8.5 to 9.0) in 2005, but then declined to 5.8 per 1000 person-years of follow-up (95% CI: 5.6 to 6.1) by 2009. The prevalence of TCVF was 0.3% (95% CI: 0.27% to 0.42%) at December 31, 2000, and then increased to 2.4% (95% CI: 2.24% to 2.50%) by the end of 2005. However, since 2005, TCVF prevalence seems to have stabilized and has remained below 3%. Conclusions: The prevalence of TCVF in people who started ART after 1998 has stabilized since around 2005, which most likely results from the decline in incidence of TCVF from this date. The introduction of improved regimens and better overall HIV care is likely to have contributed to these trends. Despite this progress, calendar trends should continue to be monitored in the long term.