Patient self-assessment (subjective measure):
We will use the BAASIS© (Basel Assessment of Adherence to Immunosuppressive Medications Scale), a 6-item scale with demonstrated psychometric properties in transplantation and other chronic diseases, as it assesses adherence according to the ABC taxonomy (Initiation, Medication Implementation, and Persistence.
The BAASIS scale has a minimum and maximum value of 6 and 30, respectively. Lower scores on the BAASIS indicate poorer adherence to immunosuppressive medications, while higher scores indicate better adherence. This self-report instrument consists of six items that assess different aspects of medication adherence, including dose taking, drug holidays, timing deviation, reduction of dose, persistence, and timing of dose taking.