Insights into reasons for discontinuation according to year of starting first regimen of highly active antiretroviral therapy in a cohort of antiretroviral-naïve patients

Objectives: The aim of the study was to determine whether the incidence of first-line treatment discontinuations and their causes changed according to the time of starting highly active antiretroviral therapy (HAART) in an Italian cohort. Methods: We included in the study patients from the Italian COhort Naïve Antiretrovirals (ICoNA) who initiated HAART when naïve to antiretroviral therapy (ART). The endpoints were discontinuation within the first year of ≥1 drug in the first HAART regimen for any reason, intolerance/toxicity, poor adherence, immunovirological/clinical failure and simplification. We investigated whether the time of starting HAART (stratified as 'early', 1997-1999; 'intermediate', 2000-2002; 'recent', 2003-2007) was associated with the probability of reaching the endpoints by a survival analysis. Results: Overall, the 1-year probability of discontinuation of ≥1 drug in the first regimen was 36.1%. The main causes of discontinuation were intolerance/toxicity (696 of 1189 patients; 58.5%) and poor adherence (285 of 1189 patients; 24%). The hazards for all-reason change were comparable according to calendar period [2000-2002, adjusted relative hazard (ARH) 0.82, 95% confidence interval (CI) 0.69-0.98; 2003-2007, ARH 0.94, 95% CI 0.76-1.16, vs. 1997-1999; global P-value=0.08]. Patients who started HAART during the 'recent' period were less likely to change their initial regimen because of intolerance/toxicity (ARH 0.67, 95% CI 0.51-0.89 vs. 'early' period). Patients who started in the 'intermediate' and 'recent' periods had a higher risk of discontinuation because of simplification (ARH 15.26, 95% CI 3.21-72.45, and ARH 37.97, 95% CI 7.56-190.64, vs. 'early' period, respectively). Conclusions: It seems important to evaluate reason-specific trends in the incidence of discontinuation in order to better understand the determinants of changes over time. The incidence of discontinuation because of intolerance/toxicity has declined over time while simplification strategies have become more frequent in recent years. Intolerance/toxicity remains the major cause of drug discontinuation. © 2009 British HIV Association.