Immunosuppressive medication adherence is paramount for optimal kidney transplant outcomes in adult recipients yet intervention testing has been scant. This pilot study is the first to examine the effectiveness and feasibility of a continuous self-improvement intervention to enhance immunosuppressive medication adherence in non-adherent adult kidney transplant patients. The continuous self-improvement intervention is unique from other interventions in that its systems approach removes motivation and remembering from medication adherence behavior. Forgetting to take medications is a frequent barrier to medication adherence (31
). Instead, daily habits and routines are linked with medication taking, and medication-taking reports from electronic monitoring provide feedback in a continuous self-improvement process. Participant acceptability and the large effect size of the continuous self-improvement intervention found in this randomized controlled trial pilot study provide early promising evidence that this approach is significantly more effective than the attention control intervention. Particularly, impressive was our finding that the intervention improved medication adherence immediately which shows its potential for one-time delivery in the hospital or outpatient setting. Our findings are consistent with other studies using a personal systems approach to change health behavior (17
). While traditional medication adherence interventions have shown modest effect sizes even when combined (educational 0.11–0.13, affective 0.18, behavioral 0.07–0.20, and combination 0.08– 0.24) (14
), this systems-focused intervention provides a promising new approach that removes blame from the patient for medication-taking failures (5
The diminishing differences between the two groups’ medication adherence score between months 5 and 6 were primarily because of an increase in the attention control group’s scores this last month (from 0.75 to 0.81). This finding may be attributed to the attention control participants’ attentiveness to medication adherence in anticipation of the return of the MEMS cap to the research team for evaluation at study end. The persistence of the intervention effect must be evaluated in a fully powered study.
Our findings show promise for possible clinical significance as well. The medication adherence score difference between the groups of 0.11 could correspond, for example, to an attention control participant taking half of the medications on time and half late (an average score of 0.75), and a continuous self-improvement participant taking 70% of the medications on time, and only 30% late (an average score of 0.85 – a difference of about 0.11). Previous studies have shown that even minor deviations in medication taking result in poor transplant outcomes (32
Future medication adherence intervention research should evaluate the potential financial benefits of the continuous self-improvement intervention once efficacy is established in a fully powered study. The economic costs of immunosuppressive medication non-adherence are high. Non-adherers experience $33 000 more in healthcare costs at the end of three yr when compared to adherers, with all but the highest medication adherers at risk for poorer health outcomes (34
). The continuous self-improvement intervention’s early impact and potential for delivery in a hospital or clinic setting make the findings of this study of interest to all transplant providers. Future research could also evaluate the efficacy of the continuous self-improvement intervention in other transplant populations.
Study conclusions must be tempered with consideration of study limitations. This study sample size was small, and the study was not powered to detect small effects, although small effects may not be clinically significant. The study was conducted with participants from a single center, so results may not be able to be generalized broadly.
In conclusion, transplant patients urgently need effective interventions for medication non-adherence. Although renal transplantation recently reached its 50-yr anniversary, clinicians have few empirically tested interventions available to assist patients with the challenging behavior of immunosuppressive adherence. This continuous self-improvement intervention shows promise as an effective and feasible approach to improve medication adherence in adult renal transplant recipients. A fully powered study with a diverse sample is needed to confirm these findings.