Adherence to tyrosine kinase inhibitors treatment in patients with chronic myeloid leukemia: single institution experience

Abstract

Introduction: Treatment adherence is an important element in the management of every chronic disease. For the patients with chronic myeloid leukemia (CML) treated with tyrosine kinase inhibitors (TKI) the remarkable benefits brought by the medication may be significantly undermined by the patient low adherence to treatment. Materials and methods: We conducted a qualitative and observational study, which was performed between October 2015 and December 2015, on patients diagnosed with CML under treatment with TKI at I-st Medical Clinic-Hematology, Clinical Emergency County Hospital Targu Mures, Romania. The sampling of patients was simple-random, consisting of 32 patients with CML-chronic phase, >18 years old, with >12 months of treatment with TKI, median age was 55 years, 67.47% of the patients were males and 62.5% of the patients were treated with imatinib 400 mg/QD. Physician-reported adherence (observed adherence) was evaluated, for the last 3 months, using the Proportion of Days Covered (PDC) method and patient-reported adherence (experienced adherence) using a self-reporting questionnaire with 10 items regarding adherence to treatment; demographic data were collected too. The following statistical analysis was used: descriptive statistic, Fisher Exact test, unpaired t-test. Results: PDC was <0.9 (low adherence) in 3 patients and 0.9-1 in 5 patients (medium adherence); Total lower adherence (low + medium) was 25%, patients being younger (p=0,044), but adherence was not correlated with gender, TKI treatment length, urban/rural place of living (p>0.05). 46.88% of the patients admit omission of doses, 73.33% of them attributing it to forgetfulness (33.33% rarely forgot, 40% sometimes), the other 26.66% to medication adverse effects or to a sense of feeling sick. Conclusion: PDC estimation of adherence was more optimistic compared to experienced adherence. Due to the unavoidable errors Associated with patient self-report, the rate of non-adherence is probably underestimated. Because the adherence to chronic medication in general and to TKI in particular is multifactorial, further quantitative, multiparameter and multicenter studies are necessary.