Measuring stigma associated with tuberculosis and HIV/AIDS in southern Thailand: exploratory and confirmatory factor analyses of two new scales

OBJECTIVE To develop scales to measure tuberculosis and HIV/AIDS stigma in a developing world context. METHODS Cross-sectional study of tuberculosis patients in southern Thailand, who were asked to rate their agreement with items measuring TB and HIV/AIDS stigma. Developing the scales involved exploratory and confirmatory factor analyses, internal consistency, construct validity, test-retest reliability and standardized summary scores. RESULTS Factor analyses identified two sub-scales associated with both tuberculosis and HIV/AIDS stigma: community and patient perspectives. Goodness-of-fit was good (TLI = 94, LFI = 0.88 and RMSEA = 0.11), internal consistency was excellent (Cronbach's alphas 0.82-0.91), test-retest reliability was moderate, and construct validity showed an inverse correlation with social support. CONCLUSION Our scales have good psychometric properties that measure stigma associated with tuberculosis and HIV/AIDS and allow assessment of stigma from community and patient perspectives. Their use will help document the burden of stigma, guide the development of interventions and evaluate stigma reduction programmes in areas with a high HIV/AIDS and tuberculosis burden.