RESUMEN
BACKGROUND AND OBJECTIVE: To know the durability of consecutive regimens of antiretroviral treatment is important to design a long-term therapy, but there is not much information about this subject. PATIENTS AND METHOD: Retrospective epidemiological study of a sample of 401 patients who began antiretroviral treatment between January 1997 and April 2000 at ten Spanish hospitals. The duration of each consecutive antiretroviral regimen was calculated and the reasons for modification and discontinuation were described. RESULTS: In the 3 years and 3 months covered by the study, 48.6% of the patients received more than one regimen of therapy. Seventy five of the initial prescribed combinations included protease inhibitors. Median duration of consecutive lines of therapy was decreasing: 560, 360, 330 and 202 days for the first, second, third and fourth regimens, respectively. The main reason to modification was intolerance or toxicity (46.2, 49.1 and 47.1% for the first, second and third modification). A fifth of changes was originated by difficulties to follow the therapy. Virological failure was the reason for modification in 21.8, 24.5 and 26.5% of first, second and third changes. CONCLUSIONS: Duration of consecutive antiretroviral regimens progressively decreases. Intolerance or drug toxicity were the main reasons conditioning the change of treatment.