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Original Investigation
October 2016

Nonadherence to Medications for Chronic Conditions and Nonadherence to Adjuvant Hormonal Therapy in Women With Breast Cancer

Author Affiliations
  • 1Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, New York
  • 2Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, New York, New York
  • 3Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York
  • 4Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, New York
  • 5Department of Obstetrics and Gynecology, College of Physicians and Surgeons, Columbia University, New York, New York
JAMA Oncol. 2016;2(10):1326-1332. doi:10.1001/jamaoncol.2016.1291
Key Points

Question  Is adherence and/or nonadherence to chronic medications associated with adherence and/or nonadherence to oral hormonal therapy (HT) in women with early-stage breast cancer?

Findings  In this retrospective cohort study of 21 255 women with breast cancer, those who used 1 or more medication(s) prior to HT and were adherent (n = 9223) had a 9.8% nonadherence rate to HT, while those who were nonadherent to their medications (n = 4214) had a 23.1% nonadherence rate to HT.

Meaning  Those who are nonadherent to chronic medications are at increased risk for nonadherence to HT and could benefit from vigilance and possible future interventions.

Abstract

Importance  While adjuvant hormonal therapy (HT) reduces mortality for women with nonmetastatic breast cancer, nonadherence to HT is common.

Objective  We investigated the association between patterns of prior nonadherence to medications for chronic conditions with HT nonadherence.

Design, Setting, and Participants  For this retrospective cohort study, the MarketScan database was scanned for women 18 years and older who had been diagnosed with nonmetastatic breast cancer between January 1, 2010, and December 31, 2012, and who filled 2 or more prescriptions for tamoxifen and/or an aromatase inhibitor.

Main Exposures and Outcomes  Nonadherence to medications for 6 chronic conditions (hypertension, hyperlipidemia, gastroesophageal reflux disease, thyroid disease, diabetes, osteoporosis) in the 12 months before diagnosis was defined as a medication possession ratio (MPR) less than 80%. Nonadherence to HT was defined as an MPR less than 80% between the first and last prescription for HT up to 2 years.

Analysis  Multivariable logistic regression was used to determine the association between prior medication nonadherence and HT nonadherence.

Results  Of 21 255 women treated with adjuvant HT, 3314 (15.6%) were nonadherent, and age (<55 or ≥75 years vs 55-64 years), higher 30-day out-of-pocket costs, and increased comorbidities were associated with nonadherence. Women without prior medications for 1 of the chronic conditions (n = 7828 [37%]) had an 18.4% nonadherence rate to HT. Those who used 1 or more medication prior to HT and were adherent (n = 9223 [43%]) had a 9.8% nonadherence rate to HT (relative to those without prior medications: odds ratio [OR] 0.56; 95% CI, 0.50-0.61), while those who were nonadherent to their chronic medications (n = 4214 [20%]) had a 23.1% nonadherence rate to HT (OR 1.43; 95% CI, 1.30-1.58). Adherence and nonadherence for medications for each of the 6 medical conditions was associated with adherence or nonadherence for HT, respectively.

Conclusions and Relevance  We found that nonadherence to medications for chronic conditions prior to HT was associated with greater nonadherence to oral HT in patients with breast cancer. Medication nonadherence history may play an important role in determining patients at risk for nonadherence to a subsequent medication for a different illness, such as HT, and a potential target for future interventions.

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