MEASURING QUALITY-OF-LIFE FROM THE POINT-OF-VIEW OF HIV-POSITIVE SUBJECTS - THE HIV-QL31

Assessment of the quality of life (QoL) of human immunodeficiency viru s (HIV)-infected subjects is often based on questionnaires in which th e items or questions are not seen to be relevant by patients, nor by t he users of the data obtained. It therefore seemed appropriate to retu rn to the issue. The methodological and bibliographical research as we ll as the consultations we conducted convinced us that the elaboration of a new questionnaire was both necessary and possible. In order to d o so, we adopted methodological principles based on the Sickness Impac t Profile development methodology. First a bibliographical research wa s conducted in order to study instruments already used for HIV infecti on. Then, experts concerned with HIV infection and members of patients ' associations were interviewed to assess how opportune the developmen t of a new instrument could be. Following this, a methodology was esta blished for the design and construction of the new instrument. One hun dred and eighteen candidate questions were generated from an analysis of the content of 20 patients' interviews, which were subsequently sub mitted to 102 patients, to obtain finally a set of 31 questions from t he interpretation of the results obtained from classic psychometric an alysis and also from non-classic methods (item response theory and Ras ch model). The concept being measured is the impact of illness being e xperienced by HIV-infected subjects from their own perspective. The ra nge of health states covered by this questionnaire relates to fairly m ild conditions. Rasch analysis of this set of 31 questions (HIV-QL31) shows that it corresponds to one unidimensional construct. A single sc ore can be calculated by simple summation of dichotomous response opti ons. This score is highly reliable (Cronbach's alpha coefficient = 0.9 3) and is also discriminant regarding the severity of clinical status.