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Effects of Previous Medication Regimen Factors and Bipolar and Psychotic Disorders on Breast Cancer Endocrine Therapy Adherence
Journal article   Peer reviewed

Effects of Previous Medication Regimen Factors and Bipolar and Psychotic Disorders on Breast Cancer Endocrine Therapy Adherence

Cole B Haskins, Joan M Neuner, Bradley D McDowell, Ryan M Carnahan, Jess G Fiedorowicz, Robert B Wallace, Brian J Smith and Elizabeth A Chrischilles
Clinical breast cancer, Vol.20(3), pp.e261-e280
06/2020
DOI: 10.1016/j.clbc.2019.09.005
PMCID: PMC7103521
PMID: 32139273

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Abstract

Endocrine therapy adherence remains a barrier to optimal estrogen receptor-positive breast cancer outcomes. We theorized that experience navigating difficult medication regimen factors, such as route of administration complexity, might improve subsequent adherence after stressful cancer diagnoses but not for patients with bipolar and psychotic disorders at risk of poor access and nonadherence. We included 21,894 women aged ≥ 68 years at their first surgically treated stage I-IV estrogen receptor-positive breast cancer (2007-2013) from the Surveillance, Epidemiology, and End Results–Medicare data set, of whom 5.8% had bipolar or psychotic disorders. We required continuous fee-for-service Medicare (parts A and B) data for ≥ 36 months before and 18 months after the cancer diagnosis. The medication regimen factors in the part D claims for 4 months before included the number of all medications used, pharmacy visits, and administration complexity (medication regimen complexity index subscale). Cox regression analysis was used to model the time to initiation and discontinuation, with longitudinal linear regression for adherence to endocrine therapy. Women with more frequent previous medication use and pharmacy visits were more likely to initiate, 4+ medications and 2+ visits versus no medication (hazard ratio [HR], 1.47; 95% confidence interval [CI], 1.33-1.63), to adhere (6.0%; 95% CI, 4.3-7.6), and to continuously use their endocrine therapy (discontinuation HR, 0.48; 95% CI, 0.39-0.59). Medication administration complexity had modest effects. Difficult medication regimens were more common for patients with bipolar and psychotic disorders but had no statistically significant effects. Experience with frequent previous medication use and pharmacy visits might increase the likelihood of endocrine therapy use for most patients but not for those with bipolar and psychotic disorders. Nonadherence to breast cancer endocrine therapy can worsen survival and recurrence risk. We examined patient medication regimens before breast cancer diagnosis, which can affect patients’ readiness for future adherence. Patients who used more medications and frequently visited pharmacies before cancer were more likely to adhere; however, subgroups with behavioral risk factors (ie, bipolar and psychotic disorders) saw no significant benefit.
Estrogen receptor Bipolar disorder SEER-Medicare Mental illness Complexity

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