Prevalence and risk factors of non-adherence with immunosuppressive medication in kidney transplant patients

Non-adherence with immunosuppressive regimen is a major risk factor for poor outcome after kidney transplantation. Identifying patients at risk for non-adherence requires understanding the risk factors for non-adherence. This prospective study included a convenience sample of 249 adult kidney transplant patients >1 year post-transplant. Non-adherence was monitored electronically using MEMS(R). Selected socio-economic, therapy-, patient-, condition- and healthcare team-related risk factors for non-adherence were assessed. Period prevalences were expressed as the percent of prescribed doses taken (taking adherence), the percent of correctly dosed days (dosing adherence), the percentage of inter-dose intervals not exceeding 25% of the prescribed interval (timing adherence), and the number of drug holidays per 100 days (no intake for > 48 h if once daily or for > 24 h if twice daily intake). Testing occurred by simple mixed logistic regression analysis. Factors significant after correction for multiple testing were entered into a multiple logistic regression model. Mean taking, dosing, timing adherence, and drug holidays were 98%, 96%, 93%, and 1.1 days, respectively. Non-adherence was associated with lower self-efficacy, higher self-reported non-adherence, no pillbox usage, and male gender. Adherence declined between Monday and Sunday. This study provides a framework for identifying patients at risk for non-adherence and for developing adherence-enhancing interventions.