Revista Panamericana de Salud Pública
On-line version ISSN 1680-5348Print version ISSN 1020-4989
PINA LOPEZ, Julio Alfonso; CORRALES RASCON, Andrés Ernesto; MUNGARAY PADILLA, Katherine and VALENCIA VIDRIO, Manuel Alejandro. Instrument for measuring psychological variables and adherence to treatment behavior in persons who are seropositive for HIV (VPAD-24). Rev Panam Salud Publica [online]. 2006, vol.19, n.4, pp.217-228. ISSN 1680-5348. http://dx.doi.org/10.1590/S1020-49892006000400001.
OBJECTIVE: To test the psychometric properties of an instrument for measuring psychological variables and adherence to treatment behaviors in persons with HIV infection or AIDS. METHODS: A cross-sectional study was performed with 68 subjects who were seropositive for the human immunodeficiency virus (HIV) and who were being treated in a health facility in the city of Hermosillo (Sonora), Mexico, at the time the study was carried out. Five consecutive statistical testing procedures were applied for data analysis: the Student t test for comparison of means, for assessing the comprehensibility of the questions; an exploratory factorial analysis with varimax rotation for determining construct validity; Cronbach's a coefficient for determining reliability; Pearson's correlation coefficient (r) for assessing concurrent validity; and multiple linear regression for determining predictive value. RESULTS: In 25 out of a total of 30 questions, the Student t test for comparison of means gave statistical significance values of P < 0.05, P < 0.005, P < 0.01, and P £ 0.001. A four-factor structure was found with the factorial analysis with varimax rotation: (1) current adherence behavior and treatment; (2) underlying reasons for adherence or lack of adherence; (3) psychological well-being and social competencies; (4) past adherence behavior with values above 1 that, taken as a whole, explain 65.50% of the variance. An overall a coefficient of 0.852 was obtained with the test for reliability. The test for concurrent validity showed correlations between factors 1 and 2 (r = 0.615; P = < 0.01), between factor 2 and factors 3 and 4 (r = -0.178; P < 0.05 and r = 0.265; P < 0,05, respectively), and between factor 3 and duration of infection in months (r = 0.265; P < 0.05). Finally, multiple linear regression showed that psychological factors 2 and 4, which together explain 48.6% of the variance, predicted current adherence behavior (adjusted determination coefficient [R2] = 0.486). CONCLUSION: According to the results obtained, the instrument has optimal reliability as well as construct validity, concurrent validity, and predictive validity.
Keywords : Patient cooperation; seropositivity; reproducibility of results; validity; Mexico.