Evaluation of factors influencing immunosuppressant adherence among heart transplant patients: FIAHT study

Introduction Each year, more than 5,000 heart transplants occur worldwide. This solution for end-stage heart failure allows to extend the survival of patients beyond 10 years and improves considerably their quality of life. However, its long-term success relies on a major element: adherence to immunosuppressants (IS). Objective The objective of our study was to assess IS adherence in heart transplant patients (HTP) followed in our hospital and to determine protective or risk factors. Method This was a descriptive, prospective, single-center study conducted between March and September 2021. Adult patients who returned home since their transplant were included. Data were collected through a self-questionnaire, a pharmacist interview, and the patient medical record. Adherence was assessed by using the Basel Assessment of Adherence to Immunosuppressive Medications Scale© (BAASIS©) interview. The different factors analyzed were either sociodemographic, clinical, therapeutic or biological. Statistical analyses (univariate and multivariate) were performed with SAS®9.04. Results One hundred eighty-two patients were included out of 210 (87%) followed in consultation in our hospital. The median age was 59 years [22–87] and 75% were men. Polypharmacy is present among 79.1% of patients, with a median of 14 units per day (9 lines of treatment). The prevalence of adherence to IS was 64%. Non-adherence was found almost exclusively in the implementation phase. It was due to missed doses (24%), missed dosing times (21%) and/or dose reduction (1%). Four factors were identified by multivariate analysis as influencing IS adherence. Having hypertension or taking corticosteroids improved adherence (P=0.048 and 0.040, respectively) whereas smoking (P=0.001) or having a history of dialysis (P=0.024) decreased it. In another hand, non-adherence was not correlated with IS concentration levels, quality of life, patient's knowledge on immunosuppressants, or the tolerance of immunosuppressive therapy. Conclusion Our study confirmed that adherence to IS in HTP remains insufficient. Furthermore, identifying risk factors is complex but crucial. The clinical pharmacist can play a key role in monitoring adherence, and in collaboration with physicians and other caregivers, may provide specific interventions to improve it.