Assessment of validity and reliability of the Tuberculosis Related Stigma Scale in Colombian patients

Objective To know the dimensionality and internal consistency of the Tuberculosis-Related Stigma Scale in patients living with tuberculosis in Santa Marta, Colombia. Method: One hundred and twenty-two patients between the ages of 18 and 75 participated (M=40.3, SD=14.9), 63.9% were men, 44.3% were single, 69.7% had low income, 80.3% had pulmonary tuberculosis, and 13.1% had co-infection with HIV. The Tuberculosis-Related Stigma Scale was applied; it is composed of two subscales: perceived and internalized stigma. The internal structure was explored by confirmatory factor analysis (EFA). Internal consistency was measured with Cronbach’s alpha and McDonald’s omega. Besides, the differential functioning of the scales according to gender was explored with Kendall’s tau-b coefficient. Results CFA did not show excellent goodness-of-fit indicators for the perceived stigma scale (Satorra-Bentler’s chi-square of 184.48, degree of freedom of 44, p=0.001, RMSEA of 0.16, 95%CI 0.14 - 0.19, CFI of 0.77, TLI of 0.72, and SRMR of 0.08) and internalized (Satorra-Bentler’s chi-square of 189.14, degree of freedom of 54, p=0.001; RMSEA of 0.14, 95%CI 0.12 - 0.17, CFI of 0.82, TLI of 0.78, and SRMR of 0.07). The alpha and omega coefficients were 0.89 and 0.91 for both scales, respectively. Non-gender differential functioning was observed; Kendall’s tau-b were between 0.00 and 0.15. Conclusions The Tuberculosis-Related Stigma Scale has an excellent internal consistency but poor goodness-of-fit indicators of unidimensionality. Evaluating the scale’s psychometric performance is recommenced in future research.