Psychological model of ART adherence behaviors in persons living with HIV/AIDS in Mexico: a structural equation analysis

ABSTRACT OBJECTIVE The objective of this study has been to test the ability of variables of a psychological model to predict antiretroviral therapy medication adherence behavior. METHODS We have conducted a cross-sectional study among 172 persons living with HIV/AIDS (PLWHA), who completed four self-administered assessments: 1) the Psychological Variables and Adherence Behaviors Questionnaire, 2) the Stress-Related Situation Scale to assess the variable of Personality, 3) The Zung Depression Scale, and 4) the Duke-UNC Functional Social Support Questionnaire. Structural equation modeling was used to construct a model to predict medication adherence behaviors. RESULTS Out of all the participants, 141 (82%) have been considered 100% adherent to antiretroviral therapy. Structural equation modeling has confirmed the direct effect that personality (decision-making and tolerance of frustration) has on motives to behave, or act accordingly, which was in turn directly related to medication adherence behaviors. In addition, these behaviors have had a direct and significant effect on viral load, as well as an indirect effect on CD4 cell count. The final model demonstrates the congruence between theory and data (x2/df. = 1.480, goodness of fit index = 0.97, adjusted goodness of fit index = 0.94, comparative fit index = 0.98, root mean square error of approximation = 0.05), accounting for 55.7% of the variance. CONCLUSIONS The results of this study support our theoretical model as a conceptual framework for the prediction of medication adherence behaviors in persons living with HIV/AIDS. Implications for designing, implementing, and evaluating intervention programs based on the model are to be discussed.

Modelo estructural predictor de la salud mental y física en mujeres / A structural equation model for predictors of mental and physical health in women

OBJETIVO: Valorar la capacidad predictora del estrés, el apoyo social y la autoestima respecto de la salud mental y física del individuo mediante ecuaciones estructurales, integrando modelos parciales estimados anteriormente, lo que permite simplificar los efectos entre las variables. MÉTODOS: La muestra estudiada abarcó 283 mujeres con hijos. Todas las participantes residían en el municipio de General Escobedo, estado de Nuevo León, México. Las encuestas se realizaron en el segundo semestre de 2003, en los domicilios, utilizando cuestionarios de autoevaluación para valorar cada una de las variables incluidas en el modelo. Cada participante respondió a los cuestionarios en una sola sesión. Los resultados se analizaron con el programa AMOS 5.0, empleando el método de máxima verosimilitud, comúnmente utilizado en los modelos de ecuaciones estructurales. RESULTADOS: Los resultados obtenidos indican un ajuste aceptable en el modelo propuesto (ji2/gl = 3,03, GFI (índice de bondad del ajuste) = 0,894, AGFI (índice de bondad del ajuste corregido) = 0,848, RMSEA (error de aproximación cuadrático medio) = 0,08, IFI (índice de ajuste incremental) = 0,910). La varianza explicada es del 31,9 por ciento respecto del estrés, del 27,4 por ciento respecto de la salud física y del 72,1 por ciento respecto de la salud mental. CONCLUSIONES: El apoyo social y la autoestima son predictores del estrés; la edad y el estrés, predictores de la salud física; y el estrés, la autoestima y la salud física, predictores de la salud mental.

OBJECTIVE: To measure the extent to which stress, social support, and self-esteem are predictors of an individual's mental and physical health. Structural equations were integrated with previously-estimated partial models, which simplify the relationships among variables. METHODS: The study sample included 283 women with children. All of the participants resided in the municipality of General Escobedo, state of Nuevo León, Mexico. The surveys were carried out in the second semester of 2003, in the participants homes, using self-evaluation questionnaires to measure each of the variables included in the model. Each participant completed the questionnaire in one sitting. Results were analyzed with AMOS 5.0, employing the maximum likelihood method, often utilized in structural equation models. RESULTS: The results indicate an acceptable adjustment in the proposed model: (chi2/gl = 3.03, goodness of fit (GFI) = 0.894, adjusted goodness of fit (AGFI) = 0.848, root mean square error of approximation (RMSEA) = 0.08, incremental fit index (IFI) = 0.910). Variances were 31.9 percent with regard to stress, 27.4 percent with regard to physical health, and 72.1 percent with regard to mental health. CONCLUSIONS: Social support and self-esteem are predictors of stress; age and stress are predictors of physical health; and stress, self-esteem, and physical health are predictors of mental health.