[Patient's understanding of information on antiretroviral therapy: an application of the latent trait model].

The aim of this study was to develop a score to determine the level of understanding regarding information on antiretroviral therapy (ART) among patients initiating treatment. This was a cross-sectional analysis based on interviews with HIV patients in outpatient public referral centers (Belo Horizonte, Minas Gerais State, Brazil). The score for patients' understanding of their medicines was obtained using a latent trait model, estimated by the Item Response Theory, based on the concordance between each patient answer and the written prescription. Hierarchical linear regression was used to assess patients' global understanding of ART, considering each class of drugs (level 1) and the individual (level 2). Among 406 patients, 37.9% failed to reach a minimum level of understanding of their treatment. The item with the highest level of difficulty was "precaution in use". The item "dosage" showed the most varied understanding of ART. A high proportion of patients displayed minimal understanding of ART, indicating a high potential risk for non-adherence to therapy. It is thus necessary to identify factors associated with insufficient understanding of ART.