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The association between trajectories of endocrine therapy adherence and mortality among women with breast cancer. Pharmacoepidemiol Drug Saf 2016 08;25(8):953-9

Date

04/30/2016

Pubmed ID

27125337

DOI

10.1002/pds.4012

Abstract

PURPOSE: Studies examining adherence to endocrine therapy (ET) and breast cancer-related outcomes have traditionally used the proportion of days covered (PDC) by medication to define adherence which may mask true treatment-outcome associations for patients with different medication use behaviors. We use group-based trajectory models to examine the association between ET adherence patterns and mortality compared to a standard PDC adherence measure.

METHODS: Using Surveillance, Epidemiology and End Results-Medicare data we included 9492 women with breast cancer who initiated ET between 2007 and 2010. We excluded women who died/recurred in the 12 months after ET initiation. We used monthly group-based trajectory models to characterize longitudinal adherence patterns and adjusted Cox proportional hazard models to estimate the association between ET adherence and mortality, comparing trajectory-based adherence to traditional PDC-based measures.

RESULTS: Trajectory models identified five adherence groups: (i) high (56.2%); (ii) quick decline (9.5%); (iii) moderate decline (7.9%); (iv) quick decline, then increase (16.0%); and (v) slow decline (10.5%). Mortality was significantly associated with group assignment; compared to the high adherers, there was a significantly higher risk of death among quick declines (HR = 1.41, 95%CI = 1.09-1.72) and moderate declines (HR = 1.25, 95%CI = 1.00-1.55). Using the standard PDC adherence measure women with adherence <80% over the year had a higher risk of death than those with adherence ≥80% (HR = 1.21, 95%CI = 1.06-1.38).

CONCLUSIONS: Defining ET adherence using trajectory models improved adherence measurement. These models could inform clinical practice by helping to identify common adherence patterns, potential areas for intervention and better isolate adherence-related outcomes in comparative effectiveness studies. Copyright © 2016 John Wiley & Sons, Ltd.

Author List

Winn AN, Dusetzina SB

Author

Aaron Winn PhD Assistant Professor in the School of Pharmacy Administration department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Aged
Aged, 80 and over
Antineoplastic Agents, Hormonal
Breast Neoplasms
Female
Humans
Longitudinal Studies
Medication Adherence
Models, Statistical
Proportional Hazards Models
SEER Program
Time Factors
Treatment Outcome
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a