Reliability and validity of Thai versions of the MOS-HIV and SF-12 quality of life questionnaires in people living with HIV/AIDS

Background/Aim: As Thai people living with HIV/AIDS gain increasing access to antiretroviral (ARV) therapy, it is important to evaluate the impact this has not only on clinical outcomes, but also on patients' functional status and well-being. In this study, we translated, culturally adapted and tested the reliability and validity of two widely-used health-related quality of life questionnaires - the MOS-HIV Health Survey and the SF-12 - in people living with HIV/AIDS in Northern Thailand. Methods: Questionnaires were administered to 100 patients at community hospital outpatient ARV clinics in northern Thailand. Reliability was estimated using Cronbach's alpha, while evidence for validity was tested using known-groups comparison based on CD4 group, symptom distress score, bed days and days of reduced activity in the past three months. Results: Patients' median age was 36, with 58% female, 58% working as laborers, and 60% completing at least primary education. Median CD4 count was 218 cells/mm(3). There were no missing data. For the MOS-HIV and SF-12, mean physical summary scores were 53.1 and 49.0 respectively; mean mental summary scores were 53.4 and 45.6, respectively. Internal consistency coefficients were > 0.7 for all but one scale, the PF scale (0.67). As hypothesized, scores were slightly to moderately correlated with CD4 count, symptom score, number of days in bed or with reduced activity. Correlations were higher with physical health scores than with mental health scales. The MOS-HIV discriminated clinical known groups slightly better than the SF-12. Conclusion: Both the MOS-HIV and the shorter SF-12 were successfully adapted for people with HIV/AIDS in Northern Thailand, and showed encouraging evidence for reliability and validity. These patient reported questionnaires could be valuable tools in evaluating therapeutic interventions and other innovations in health and social services, and to estimate health needs and population disability related to HIV.