Assessing medication adherence in solid-organ transplant recipients.

OBJECTIVES

We sought to determine and compare the prevalence of nonadherence in lung, kidney, and liver transplant recipients, and identify potential risk factors for nonadherence.

MATERIALS AND METHODS

This cross-sectional, single-center, retrospective cohort study, evaluated 225 outpatient lung, kidney, and liver transplant recipients' adherence to immunosuppressant medication. Based on immunosuppressant dosages and dispensing records, medication possession ratio (days of medication supplied/actual days) and gaps in prescription refills (> 30-day lapse between expected depletion of supply and next refill) were used as surrogate markers in assessing adherence for 2 years. Patients were adherent to their immunosuppressant medication regimens if their medication possession ratio was ≥ 80%.

RESULTS

The mean age of the subjects was slightly greater than 50 years of age, and they were a median of 2.0, 1.3, and 1.1 years posttransplant at the start of data collection for lung, kidney, and liver recipients. Overall medication possession ratios were 95.4% ± 7.5%, 95.9% ± 7.6%, and 92.7% ± 12.3% in our lung, kidney, and liver recipients. Only 7.1% of patients had a medication possession ratio lower than 80%, which was the cutoff for nonadherence. No statistical analyses were performed to identify potential factors for nonadherence because of the small number of nonadherent patients.

CONCLUSIONS

Immunosuppressant medication adherence at our center was high for all 3 organ cohorts, as measured by a medication possession ratio of 80% or better. Further study is needed to evaluate immunosuppressant adherence over time after transplant, and confirm the clinical factors that optimize adherence in high-risk patients.