Adherence of Renal Transplant Recipients to Once-daily, Prolonged-Release and Twice-daily, Immediate-release...

In this study we investigated medication adherence of kidney transplant patients (KTPs) to an immediate-release tacrolimus (IR-T) regimen and, after conversion, to a prolonged-release tacrolimus (PR-T) regimen in routine clinical practice.

This was a non-interventional, observational, multicenter Swedish study. We included adult KTPs with stable graft function, remaining on IR-T or converting from IR-T to PR-T. Data were collected at baseline, and months 3, 6, and 12 post-baseline. The primary endpoint was adherence using the Basel Assessment of Adherence to Immunosuppressive Medication Scale (BAASIS^©). Secondary assessments included tacrolimus dose and trough levels, clinical laboratory parameters (eg, estimated glomerular filtration rate), and adverse drug reactions (ADRs).

Overall, data from 233 KTPs were analyzed (PR-T, n = 175; IR-T, n = 58). Mean change in PR-T dose from baseline (4.8 mg/d) to month 12 was -0.2 mg/d, and for IR-T (4.2 mg/d) was -0.4 mg/d; tacrolimus trough levels remained similar. Overall adherence was similar between baseline and month 12 in both groups (PR-T: 54.4% vs 57.0%, respectively; IR-T: 65.5% vs 69.4%); timing adherence followed a similar pattern. The probability of taking adherence improved between baseline and month 12 (odds ratio, 1.97; P = .0092) in the PR-T group only. Mean BAASIS visual analog scale score at baseline was 94.3 ± 11.1% (PR-T) and 95.3 ± 7.6% (IR-T), and >95% at subsequent visits. Laboratory parameters remained stable. Eight (4.6%) patients receiving PR-T (none receiving IR-T) had ADRs considered probably/possibly treatment-related.

Disparity existed between high, patient-perceived and low, actual adherence. Overall adherence to the immunosuppressive regimen (measured by BAASIS) did not improve significantly over 12 months in stable KTPs converting to PR-T or remaining on IR-T; renal function remained stable.