12. Emma Keane, BA

Immunosuppressant (i.e., tacrolimus or sirolimus) adherence is crucial for treatment and recovery following hematopoietic stem cell transplantation (HSCT). However, there is limited data on the methods to measure medication adherence. This study measured immunosuppressant adherence in 150 patients with hematologic malignancies undergoing HSCT using pill counts, medication level assessment, and the Medication Adherence Response Scale-5 (MARS-5) at 30, 100, and 180 days post-HSCT. Kappa analysis was used to evaluate the agreement among different adherence measures. Univariate regression models examined the relationship between participant characteristics and medication adherence. The average age of participants was 57.5 years (SD = 13.5); 40.7% (n = 61) were female, 85.3% (n = 128) were non-Hispanic White, and 73.3% (n=110) were married or living with someone. Medication adherence varied across time points; it was 52-64% for pill counts, 18-24% for medication levels, and 97-98% for MARS-5. There was limited to no agreement between the objective and subjective measures of immunosuppressant medication adherence in patients undergoing HSCT. No participant characteristics were significantly associated with immunosuppressant adherence. Considering the complex and dynamic medication regimen of patients undergoing HSCT, measuring and interpreting adherence is likely multifaceted. Larger studies are needed to better understand immunosuppressant adherence in diverse populations.