Predictive patterns of early medication adherence in renal transplantation

Background. Patients' adherence with posttransplant immunosuppression is known to affect renal transplant outcomes. Methods. Prospectively, individual medication adherence patterns in 195 kidney transplant recipients were quantified with electronic medication monitors. Monitored drugs were mycophenolate mofetil, sirolimus, or azathioprine. Monitoring began at hospital discharge and continued an average of 15±8 months. Patient follow-up for clinical outcomes averaged 8±3 years. Each month's adherence percentage was calculated as the sum of daily adherence percents, divided by the number of evaluable days. Results. During the first 3 months after transplantation, patients (n=44) with declining medication adherence, defined as dropping by 7% or higher (equal to missing 2 days) between months 1 and 2, later experienced lower mean medication adherence for months 6 to 12, 73% versus 92% respectively (PG0.0001). Compared to patients with stable adherence, they also had more frequent (P=0.034) and earlier (P=0.065) acute rejection episodes. This was additionally associated with more frequent (P=0.017) and earlier (P=0.046) death-censored graft loss. In addition, daily medication adherence, expressed as the percentage of doses taken, decreased as the number of prescribed daily doses increased. During the first 3 months after transplantation, adherence with four doses per day averaged 84%, compared to 91% for patients on twice-daily dosing (P=0.024) and 93.5% for patients on once-daily dosing (P=0.008). Conclusions. Early declining medication nonadherence is associated with adverse clinical outcomes. This pattern is detectable during the first 2 months after transplantation. Early detection of nonadherence provides opportunities to target interventions toward patients at the highest risk for adverse behaviors and events.