Timing of antiretroviral therapy initiation after a first AIDS-defining event: temporal changes in clinical attitudes in the ICONA cohort.

Background: Time of starting antiretroviral therapy (ART) after diagnosis of specific AIDS-defining event (ADE) is a crucial aspect. Objectives of this study were to evaluate if in patients diagnosed with ADE the time to ART initiation may vary according to year of diagnosis and type of ADE.

Methods: All HIV+ persons diagnosed with an ADE over the 6 months prior to or after enrolment in the Icona Foundation study cohort and while ART-naive were grouped according to type of diagnosis: Those with ADE requiring medications interacting with ART [group A], those with ADE treatable only with ART [B] and other ADE [C]. Survival analysis by Kaplan-Meier was used to estimate the percentage of people starting ART, overall and after stratification for calendar period and ADE group. Multivariable Cox regression model was used to investigate association between calendar year of specific ADE and time to ART initiation.

Results: 720 persons with first ADE were observed over 1996-2013 (group A, n=171; B, n=115; C, n=434). By 30 days from diagnosis, 27% (95% CI: 22-32) of those diagnosed in 1996-2000 had started ART vs. 32% (95% CI: 24-40) in 2001-2008 and 43% (95% CI: 33-47) after 2008 (log-rank p=0.001). The proportion of patients starting ART by 30 days was 13% (95% CI 7-19), 40% (95% CI: 30-50) and 38% (95% CI 33-43) in ADE groups A, B and C (log-rank p=0.0001). After adjustment for potential confounders, people diagnosed after 2008 remained at increased probability of starting ART more promptly than those diagnosed in 1996-1999 (AHR 1.72 (95% CI 1.16-2.56).

Conclusions: In our "real-life" setting, the time from ADE to ART initiation was significantly shorter in people diagnosed in more recent years, although perhaps less prompt than expected.