Using The Theory Of Planned Behavior (TPB) To Investigate The Factors Of Immunosuppressive Medication Adherence Among Liver Transplant Recipients

Objective:(1) to evaluate the prevalence of nonadherence to ISM among liver transplant recipients. (2) to construct medication adherence model based on the theory of planned behavior, to verify applicability of the model and to explore the impact of latent variables on medication adherence and behavior intention.Methods:A cross-sectional design was used in this study. Three hundred liver transplant recipients were recruited by convenience sampling in a three tertiary-care hospital in Beijing from April 2015 to November 2015. Basel Assessment of Adherence with Immunosuppressive medication Scale (BAASIS), Theory of planned behavior (TPB) instrument for 1ST adherence, Beliefs about Medication Questionnaire (BMQ), Perceived social support scale (PSSS) were finished by the recipients themselves. IBM SPSS 21.0 software was used for statistical analysis. Structural equation model was used to explore the impact of latent variables on medication adherence and behavior intention by AMOS (Analysis of Moment Structures).Results:A convenience sample of 293 subjective was included, with a mean age of 61.48 years (SD 5.22). The median duration foliowingup was 3.92 years (range 0.25-26.18 years). Most of the recipients were male (76.11%). More than half (n=167,56.99%) of the recipients reported nonadherence with a score of above 4.Results of structural equation model showed that the medication adherence could be accounted for 27.5% of the variance (R2=0.275). Social support with the highest overall effect in medication adherence (coefficient of effect -0.624), medication intention could influence medication adherence directly with oath coefficients of -0.151, and medication attitude (-0.151), subjective norm (-0.109), perceived control (-0.109), past behavior (-0.007) and medication beliefs (-0.007) could influence medication adherence indirectly via mediators of Medication intention. Medication intention can be explained 73.1% of the variance with medication attitude 0.220), subjective norm (0.727), perceived control (0.314), past behavior (0.044), social support (0.314) and medication beliefs (0.149).Statistically significant differences of medication adherence were found on gender, employment status, time since transplantation, and whether had complication and rejection reaction occurrence.Conclusion:There is a high livel of medication nonadherence in liver transplant recipients. The structural equation model based on theory of planned behavior has a good ability to explain medication adherence and medication intention in liver transplant recipients. Results of this study indicate that social support is the key factor that affects medication adherence, followed by medication intention, subjective norm. In order to improve medication adherence, intervention to enhance liver transplant recipients’ social support network should be the priority. In addition, gender, employment status, time post-transplant, and whether had complication and rejection reaction occurrence have significant impacts on medication adherence.