Drivers and Barriers to Medication Adherence in Patients with Chronic Myeloid Leukaemia: A Qualitative Study

With the introduction of tyrosine kinase inhibitors (TKI), patients with chronic myeloid leukemia (CML) have obtained survival rates close to normal. It may appear paradoxical, then, that medication adherence is suboptimal in some health care settings. As the first of its kind, this study aimed to explore drivers and barriers to TKI treatment adherence in Danish CML patients. A literature study informed the design of qualitative interviews with 20 patients, individually and in focus groups, focusing on their disease perceptions of CML, their health-related quality of life (QoL) and medication adherence. The study showed that many participants had previously switched treatment due to lacking efficacy or intolerance but most felt their current disease burden was tolerable. Anxiety might, however, resurface if treatment stopped working or with the occurrence of infections or side effects, creating a state of ‘fragile peace’. To these patients, their role functioning – as professionals, spouses, parents and grandparents – was crucial to uphold a positive self-image and meaningful life. Whether treatment enabled or hindered this was thus decisive to their QoL and medication adherence. Our participants expressed high adherence rates with only one having intentionally non-adhered due to side effects and poor QoL. Most participants felt well-informed about CML and treatment and privileged to receive specialised personal care from the public health care system acting to motivate their medication adherence. As a novel finding, this study indicates that the prospect of treatment-free remission may positively affect adherence. We suggest this should be explored in future studies. J O U R N A L O F H E M A T O L O G Y A N D O N C O L O G Y R E S E A R C H ISSN NO: 2372-6601 Research Article DOI : 10.14302/issn.2372-6601.jhor-17-1761 Corresponding author: Gitte Lee Mortensen MSc, medical anthropologist , AnthroConsult, Fynsgade 24, 8000 Aarhus C, Denmark, Email: glm@anthroconsult.dk, Tel.: +45 23964252 Running line: Drivers and barriers to adherence in chronic myeloid leukemia


Introduction
Chronic myeloid leukaemia (CML) constitutes approximately 15% of adult leukaemia cases. It affects slightly more men than women and has an average onset at 64-68 years. Most patients (60-85%) are diagnosed in the initial chronic phase (CP-CML) based on symptoms such as night sweats, abdominal pain, infections, fatigue, weight loss, or bruising [1][2][3].
15-40% are asymptomatic and often identified by routine blood tests. If untreated, CP-CML will progress to an accelerated phase (AP-CML) and a fatal blast phase (BP-CML) in three to five years [1,4,5].
With the introduction of the tyrosine kinase inhibitor (TKI) imatinib in 2001, CML patients have obtained revolutionary survival rates close to normal [6].
Three levels of TKI treatment response may be obtained: complete hematologic, cytogenetic, and molecular responses (CHR, CCyR, and CMR) reflecting successive decrease in leukemic cells [4]. Efficacy is highest in CP-CML and certain milestone responses should occur within 3, 6, and 12 months after initiating treatment [4,22]. Treatment should be re-evaluated if milestones are not reached [23,24]. Response rates are deeper and faster with 2 nd generation TKIs compared to imatinib, and patients with rapid response have better long-term outcomes than those with slower or no response to therapy [11,13,17,20,22]. Yet imatinib is still the most widely used TKI due to cost-effectiveness and acceptable side effects. CML patients with long-lasting sustained CMR, amounting to 10-15% of patients, may be eligible for discontinuation [9,12,16,18,25].
The aim with the present study was to explore in depth the drivers and barriers to CML patients' adherence in a Danish health care setting.

Materials and methods
We used qualitative methods in order to   [3,6,7,11,12,14,26,[28][29][30][31]33,35,38]. Our participants described their role functioning as crucial to uphold a positive self-image and normality, which they felt was vital to a meaningful life. Symptoms thus became especially burdensome when negative affecting identity and social relations.
Only one participant had intentionally nonadhered to TKI treatment and few had considered it.