Interview guides subject areas.

An oral two-drug regimen (O2DR) in the form of a once-a-day single tablet is now recommended for treatment switching and treatment initiation for HIV. In clinical care, the process of treatment change refers to adaptation issues, both individual and within the care relationship. The study aim is to present the determinants involved in the acceptability of switching to O2DR in the PROBI (Patient-Reported Outcomes BItherapy) qualitative study. The study includes 30 interviews: 15 were conducted with doctors caring for people living with HIV, 15 were conducted with patients who had been offered a change of treatment. A double analysis was carried out: lexicometric analysis to highlight the structuring of the discourse around the change in treatment and a thematic analysis to understand the associated issues more precisely. The results highlighted common concerns with respect to switching to O2DR. Also, the caregiver-patient relationship was a central determinant in treatment switching. Information, knowledge and representations of O2DR are also factors facilitating treatment change and should be taken into account for doctors’ and patients’ adherence.