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Adherence to tyrosine kinase inhibitors among Medicare Part D beneficiaries with chronic myeloid leukemia
Author(s) -
Shen Chan,
Zhao Bo,
Liu Lei,
Shih YaChen Tina
Publication year - 2018
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.31050
Subject(s) - medicine , medicare part d , odds ratio , confidence interval , myeloid leukemia , logistic regression , epidemiology , medical prescription , prescription drug , pharmacology
BACKGROUND Tyrosine kinase inhibitors (TKIs) improve the survival of patients with chronic myeloid leukemia (CML) dramatically; however, nonadherence to TKI therapy may lead to resistance to the therapy. TKIs are very expensive and are covered under Part D insurance for Medicare patients. To the authors' knowledge, the impact of low‐income subsidy status and cost sharing on adherence among this group has not been well studied in the literature. METHODS Surveillance, Epidemiology, and End Results (SEER) registry data linked with Medicare Part D data from the years 2007 through 2012 were used in the current study. The authors identified 836 patients with CML with Medicare Part D insurance coverage who were new TKI users. Treatment nonadherence was defined as a binary variable indicating the percentage of days covered was <80% during the 180‐day period after the initiation of TKI therapy. Logistic regression was used to examine the relationship between out‐of‐pocket costs per 30‐day drug supply, Medicare Part D plan characteristics, and treatment adherence while controlling for other patient characteristics. RESULTS Overall, 244 of the 836 patients with CML (29%) were nonadherent to targeted oral therapy during the 180 days after the initiation of treatment with TKIs. The multivariable logistic regression demonstrated that patients with heavily subsidized (odds ratio, 6.7; 95% confidence interval, 2.8‐15.9) and moderately subsidized (odds ratio, 3.0; 95% confidence interval, 1.4‐6.5) Medicare Part D plans were much more likely to demonstrate nonadherence compared with patients without a subsidy. CONCLUSIONS The current population‐based study found a significantly higher rate of nonadherence among heavily subsidized patients with substantially lower out‐of‐pocket costs, which suggests that future research is needed to help lower the nonadherence rate among these individuals. Cancer 2018;124:364‐73 . © 2017 American Cancer Society .