Adherence to Immunosuppressants among Adult Patients after Allogeneic Hematopoietic Stem-Cell Transplantation (Allo-HSCT): A Cross-Sectional Study.

Background: The level of adherence to drug therapy after allogeneic hematopoietic stem-cell transplantation (Allo-HSCT) can affect the patient's outcome, and poor adherence is one of the factors in first-year mortality after HSCT. Material and Methods: This study assessed adherence to cyclosporine and prednisolone as the immunosuppressant regimen in 110 post-HSCT patients (> 18 years). Demographic characteristics, clinical information, and cyclosporine levels were obtained. A validated Persian medication adherence scale was used to assess adherence to cyclosporine and prednisolone. Results: For 110 patients, the calculated mean of the total score of cyclosporine and prednisolone was 7.73 ± 0.62 and 7.63 ± 0.73, respectively. Poor adherence to medication in this population was 27.7% and 22.7% to prednisolone and cyclosporine, respectively. A significant correlation was observed between adherence total score and cyclosporine levels at the third- and fourth-month post-transplant (r = 0.52, P < 0.001 and r = 0.60, P = 0.001). In the first, second, and third months, the mean of cyclosporine levels in the high adherence level was higher than the moderate and poor adherence levels. Additionally, there was an association between adherence score and the level of cyclosporine. One score increase in adherence scale on average increased cyclosporine level by 34.48 ng/ml. Conclusion: In this study, medication non-adherence was high, which indicates the need for more careful monitoring of post-HSCT patients' medication use. This is even more crucial currently since it has been confirmed that adherence can affect cyclosporine levels as the most effective immunosuppressant agent in preventing graft-versus-host disease (GVHD).