An observational study of health literacy and medication adherence in adult kidney transplant recipients

BACKGROUND There is a high prevalence of non-adherence to immunosuppressants in kidney transplant recipients. Although limited health literacy is common in kidney recipients and is linked to adverse outcomes in other medical populations, its effect on medication adherence in kidney transplant recipients remains poorly understood. The objective was to investigate the effect of lower health literacy on immunosuppressant adherence. METHODS Kidney recipients who were at least 6 months post-transplant and outpatients of Vancouver General Hospital in B.C., Canada were recruited through invitation letters. A total of 96 recipients completed the Health Literacy Questionnaire, which provides a multifactorial profile of self-reported health literacy and the Transplant Effects Questionnaire-Adherence subscale measuring self-reported immunosuppressant adherence. Hierarchical linear regression was used to analyze the association between health literacy and adherence after controlling for identified risk factors of non-adherence. RESULTS Our sample was on average 53 years old, 56% male and 9 years post-transplant. Kidney recipients reported low levels of health literacy on scales measuring active health management and critical appraisal of information and 75% reported non-perfect adherence. Worse adherence was associated with poorer overall health literacy (ΔR2 = 0.08, P = 0.004) and lower scores on six of nine of the health literacy factors. CONCLUSIONS Poorer health literacy is associated with lower immunosuppressant adherence in adult kidney transplant recipients suggesting the importance of considering a recipient's level of health literacy in research and clinical contexts. Medication adherence interventions can target the six factors of health literacy identified as being risk factors for lower medication adherence.