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.
From the aUniversity of Liverpool Management School, Chatham Street, L69 7ZH, Liverpool, UK
bMRC/UVRI Uganda Research Unit on AIDS in Uganda, C/O Uganda Virus Research Institute, P.O. Box 49, Entebbe, Uganda
cLiverpool School of Tropical Medicine, Pembroke Place, L35 QA, Liverpool, UK
dImperial College, Infectious Disease Section, Faculty of Medicine, Medical School, Norfolk Place, W2 1PG, London, UK.
Correspondence to Antonieta Medina Lara, University of Liverpool Management School, Chatham Street, L69 7ZH, Liverpool, UK. E-mail: firstname.lastname@example.org