Differential Effects of Psychological Factors on Adherence to Immmunosuppressant Medications Across Diverse Ethnic Kidney Transplant Populations

Abstract

Background: Kidney transplantation is the treatment of choice for individuals with end-stage renal disease despite the requirement to strictly adhere to a regimen of immunosuppressant medications to prevent graft rejection. The relationships between demographic and psychosocial factors and adherence to immunosuppressant medications have not been fully understood. This study examined: 1) depression as a significant predictor of immunosuppressant medication adherence after controlling for known demographic predictors of adherence 2) self-reported barriers to immunosuppressant medication adherence as a significant predictor of immunosuppressant medication adherence after controlling for known demographic predictors of adherence and depressive affect 3) levels of medication adherence among three ethnic groups and the possibility that any difference is explained by differing ethnic beliefs about the necessity of immunosuppressant medications. Methods: The sample consisted of 312 renal patients at least 6 months post-transplant recruited from three transplant centers in New York City: SUNY Downstate Medical Center in Brooklyn, Montefiore Medical Center in the Bronx, and Weill Cornell Medical Center in Manhattan. In addition to answering demographic questions, participants completed measures of depressive affect, immunosuppressant medication adherence, barriers to immunosuppressant medications, and beliefs about medications. The data were analyzed cross-sectionally. Results: Correlational analyses indicate that depression symptoms (rho = -.143, p < .05) and an increased number of barriers to medication adherence (rho = -.242, p < .01) are associated with lower rates of adherence to immunosuppressant medication. A hierarchical regression analysis demonstrates, consistent with bivariate analysis, that respondents reporting greater levels of depression also report lower levels of treatment adherence, even after controlling for the other demographic predictors in the model (beta = -.19, p &le; .05). Similarly, a hierarchical regression analysis of the association between reported barriers to medication adherence and lower levels of treatment adherence remains marginally significant (beta = -.13, p = .056) even after controlling for demographic predictors and depression. The final hierarchical regression showed that contrary to expectation, ethnicity was not significantly related to treatment adherence (R2 change = .00, p > .05). Conclusions: The present findings suggest that it is important to consider psychosocial factors, such as depression and barriers to medication adherence when treating renal transplant patients.