Objective: To assess the psychometric performance of using standard gamble (SG), time trade-off (TTO) and visual analogue scale (VAS) in the evaluation of three predetermined HIV/AIDS health states in HIV-infected Ugandans, for use in cost-effectiveness analyses.
Methods: We recruited participants with CD4 cells <200/μl from the Development of AntiRetroviral Therapy in Africa (DART) trial cohort [randomized trial evaluating antiretroviral therapy (ART) management strategies] in Uganda, before they initiated ART (n = 276). A comparison group of ART-naive HIV-infected individuals was recruited from the Entebbe Cohort study (n = 159). Participants were interviewed and asked to rate his/her own health state using VAS; rank and evaluate HIV/AIDS predetermined health states using TTO and SG relative to an improved health state. Tools were tested for psychometrical properties.
Results: Women constituted 64% and 76% of the DART and Entebbe Cohorts. Mean age was 36.5 and 36.7 years, respectively. Participants could discriminate between predetermined HIV/AIDS health states. Deterioration in health status was associated with a reduction in rating scores (VAS), increased willingness to give up time (TTO) and acceptance of increased risk (SG) to achieve a better health state, independent of the participant's actual health state, as measured by CD4 cell counts.
Conclusion: VAS, TTO and SG have good psychometric properties, making them good candidates for use in resource-constrained settings. Further research in a wider population is necessary to generate an evidence base with which to inform resource allocation decisions.