Medication non-adherence is a major public health issue that is associated with poor clinical and economic outcomes. Medication adherence needs to be regarded as the 5th vital sign and adequate measurement is therefore crucial. The Basel Assessment of Adherence to Immunosuppressive Medication Scale (BAASIS©) was developed to assess adherence to immunosuppressive drugs in adult and adolescent transplant recipients. The BAASIS© can also be easily adapted to assess medication adherence in other chronically ill patient populations. The BAASIS© follows the ABC taxonomy of medication adherence (Vrijens et al., 2012) which defines adherence as «the process by which patients take their medication as prescribed». This taxonomy indicates that adherence consists of 3 quantifiable phases: «initiation, implementation and persistence». All three phases are assessed by the BAASIS©. The BAASIS© exists both in interview and written self-report format in different languages. An explanation of the BAASIS© can be found here. The BAASIS© validity has been analysed psychometrically in a meta-analysis of individual patient data (Denhaerynck et al., 2023; commentary: Elias et al., 2023). Denhaerynck K, Dobbels F, Košťálová B, De Geest S; BAASIS consortium. Psychometric Properties of the BAASIS: A Meta-analysis of Individual Participant Data [published online ahead of print, 2023 Mar 23]. Transplantation. 2023;10.1097/TP.0000000000004574. doi:10.1097/TP.0000000000004574 Elias C, Cherukuri A. BAASIS for Monitoring Therapy Nonadherence in Clinical Transplantation: Are We There Yet? [published online ahead of print, 2023 Mar 23]. Transplantation. 2023;10.1097/TP.0000000000004575. doi:10.1097/TP.0000000000004575 Vrijens B, De Geest S, Hughes D, Kardas P, Demonceau J, Ruppar T, Dobbels F, Fargher E, Morrison V, Lewek P, Matyjaszczyk M, Mshelia C, Clyne W, Aronson JK, Urquhart J for the ABC project team. A new taxonomy for describing and defining adherence to medications. British Journal of Clinical Pharmacology 2012; 691-705. doi:10.1111/j.1365-2125.2012.04167.x
Other validation studies addressing predictive validity of the BAASIS© are in progress (Dr. Frederik Haupenthal, Research Group Professor Dr. Gregor Bond – University Hospital Vienna, Austria).
