Background: Although non-compliance with immunosuppression therapy is increasingly recognized as a risk factor for morbidity and mortality after heart transplantation (HTX), evidence for this association is limited to 1 prospective study that assessed medication non-compliance in the early post-HTX period and used self-report. The current prospective HTX cohort study explores the predictive value of late non-compliance (>1 year after HTX) during a 5-year follow-up using the Medication Event Monitoring System (MEMS) for compliance assessment.
Methods: We categorized 101 patients (86% men; aged 55 +/- 10 years; time after HTX at inclusion, 1,253 +/- 534 days) as medication non-compliers (n = 17) or compliers (n = 84) based on the MEMS. Late acute rejections, transplant coronary artery disease (TxCAD), retransplantation, and death were registered during the 5-year follow-up.
Results: Non-compliers had significantly more TxCAD (p = 0.025). Non-compliers also had a greater rate of late acute rejection (11.8% vs 2.4%) and retransplantation (13.3% vs 2.5%)), although these differences were not statistically significant. Mortality rates were similar. Kaplan Meier analysis showed that non-compliers had a significantly shorter clinical-event-free time compared with compliers (mean, 1,318 vs 1,612 days; p = 0.043). Cox regression analysis showed that the adjusted relative risk associated with non-compliance was 2.03 (p = 0.0582), after controlling for other known transplant-related risk factors for poor clinical outcome.
Conclusion: The current study demonstrates that medication non-compliance in the late post-transplant period doubles the risk for an untoward clinical event. Non-compliance is a continuous risk factor after heart transplantation that should be targeted by compliance-enhancing interventions.