Patient factors associated with adherence to immunosuppressant therapy in renal transplant recipients

Abstract

Factors associated with adherence to immunosuppressant therapy (IST) in renal transplant recipients were studied. The Immunosuppressant Therapy Adherence Scale (ITAS) was completed by adult renal transplant recipients in Georgia. Those completing the ITAS were classified as adherent to IST if their ITAS score were 12 and nonadherent if their score was less than 12. The relationship between the dichotomized ITAS scores and patient variables that are readily available to clinicians, such as sex, age, kidney donor type, income, marital status, race or ethnicity, and time since transplantation, was assessed. The relationship of ITAS scores to patients' clinical and pharmacy data (e.g., graft rejection, serum IST concentrations, serum creatinine [SCr] concentrations, and pharmacy refill-based adherence rates) was also assessed. One hundred thirty-seven patients completed the ITAS. Eighty-nine patients (65%) were adherent to IST, and the remaining 48 (35%) were nonadherent. Patient sex was unrelated to adherence. Compared with nonadherent patients, adherent patients tended to be younger, to take cyclosporine, to have lower incomes, to have received their transplant more recently, to have targeted immunosuppressant concentrations, to have greater refill-based adherence rates, and to be less likely to exhibit an increase in SCr concentration (p < 0.05). There was no significant difference in the number of rejections between adherent and nonadherent patients. Patient age, income, time since transplantation, and the immunosuppressant agent prescribed were associated with IST adherence.