Assessment and Treatment of Nonadherence in Transplant Recipients

Comparison of different methods to assess tacrolimus concentration intra-patient variability as potential marker of medication non-adherence

Background and objective: Non-adherence to tacrolimus commonly manifests as low drug concentrations and/or high intra-patient variability (IPV) of concentrations across multiple measurements. We aimed to compare several methods of tacrolimus IPV calculation and evaluate how well each reflects blood concentration variation due to medication non-adherence in kidney transplant recipients.

Methods: This Czech single-center retrospective longitudinal study was conducted in 2019. All outpatients ≥18 years of age, ≥3 months post-transplant, and on tacrolimus-based regimens were approached. After collecting seven consecutive tacrolimus concentrations we asked participating patients to self-report adherence to immunosuppressants (BAASIS^© scale). The IPV of tacrolimus was calculated as the medication level variability index (MLVI), the coefficient of variation (CV), the time-weighted CV, and via nonlinearly modeled dose-corrected trough levels. These patient-level variables were analyzed using regression analysis. Detected nonlinearities in the dose-response curve were controlled for by adding tacrolimus dosing and its higher-order terms as covariates, along with self-reported medication adherence levels.

Results: Of 243 patients using tacrolimus, 42% (n = 102) reported medication non-adherence. Non-adherence was associated with higher CVs, higher time-weighted CVs, and lower dose-corrected nonlinearly modeled trough levels; however, it was not associated with MLVIs. All of the significant operationalizations suggested a weak association that was similar across the applied methods.

Discussion and conclusion: Implementation non-adherence was reflected by higher CV or time-weighted CV and by lower blood concentrations of tacrolimus. As an additional tool for identifying patients at risk for non-adherence, simple IPV calculations incorporated into medical records should be considered in everyday clinical practice.

Remote intervention engagement and outcomes in the Clinical Trials in Organ Transplantation in Children consortium multisite trial

Remote interventions are increasingly used in transplant medicine but have rarely been rigorously evaluated. We investigated a remote intervention targeting immunosuppressant management in pediatric lung transplant recipients. Patients were recruited from a larger multisite trial if they had a Medication Level Variability Index (MLVI) ≥2.0, indicating worrisome tacrolimus level fluctuation. The manualized intervention included three weekly phone calls and regular follow-up calls. A comparison group included patients who met enrollment criteria after the subprotocol ended. Outcomes were defined before the intent-to-treat analysis. Feasibility was defined as ≥50% of participants completing the weekly calls. MLVI was compared pre- and 180 days postenrollment and between intervention and comparison groups. Of 18 eligible patients, 15 enrolled. Seven additional patients served as the comparison. Seventy-five percent of participants completed ≥3 weekly calls; average time on protocol was 257.7 days. Average intervention group MLVI was significantly lower (indicating improved blood level stability) at 180 days postenrollment (2.9 ± 1.29) compared with pre-enrollment (4.6 ± 2.10), p = .02. At 180 days, MLVI decreased by 1.6 points in the intervention group but increased by 0.6 in the comparison group (p = .054). Participants successfully engaged in a long-term remote intervention, and their medication blood levels stabilized. NCT02266888.

Prevalence and Risk Factors of Immunosuppressant Nonadherence in Heart Transplant Recipients: A Single-Center Cross-Sectional Study

BACKGROUND

Immunosuppressant nonadherence (INA) has been shown to affect outcomes after solid organ transplantation. The aim of the present study was to determine the prevalence of INA in heart transplant recipients and the associated risk factors of INA.

METHODS

Adult heart transplant recipients who firstly received heart transplantation (discharged for at least 3 months) were consecutively enrolled. Immunosuppressant adherence was assessed using the Basel Assessment of Adherence with Immunosuppressive Medication Scale (BAASIS). INA was categorized into five domains of contributing factors (socio-demographic factors, transplant-related factors, healthcare system access factors, post-transplant treatment-related factors, and patient-related psychosocial factors). These factors were compared between adherent and nonadherent patients. The risk factors of INA were investigated by logistic regression analysis.

RESULTS

A total of 168 heart recipients were ultimately included. Among them, 69 (41.1%) recipients were revealed to be nonadherent. Logistic regression analysis indicated that INA was associated with monthly income<3000 Chinese Yuan (CNY) (OR, 3.11; 95% CI, 1.58-6.12; p=0.001), number of prescribed concomitant drugs (OR, 1.23; 95% CI, 1.12-1.50; p=0.003) and concerns about immunosuppressants (OR, 1.09; 95% CI, 1.01-1.18; p=0.031).

CONCLUSIONS

Heart recipients had a high prevalence of INA. Lower income, greater number of prescribed concomitant drugs, and more concerns about immunosuppressants correlated most with timing nonadherence and taking nonadherence among heart recipients. These findings will be helpful to intervene on and prevent future INA of heart recipients.