Time perspective: Collection of historical data and longitudinal follow up. Patients will be enrolled in 2011/2012 but data will be collected from medical charts from ATV initiation date (Feb 2008 - July 2010) until July 2013 at the latest (if no ATV discontinuation, or death, or lost to follow up).
Non probability sample:
* Specialized HIV management centers will be contacted in order to recruit about 15-20 sites per country.
* Each site will have to enroll an average of 8-12 consecutive patients (min:5; max:30) fulfilling the inclusion/exclusion criteria.
