Simulating Time-Dependent Patterns of Nonadherence by Patients With Breast Cancer to Adjuvant Oral Endocrine Therapy.

Eileen H Shinn,Ainslee Johnson,Stacy Moulder,William Fraser Symmans,Elizabeth Wieland,Bryan Fellman,Gordon Broderick

doi:10.1200/cci.18.00091

Abstract

PURPOSENearly 40% of patients with breast cancer discontinue their adjuvant oral endocrine treatment (ET). We measured discontinuation rates of ET at a comprehensive cancer center. We then used an iterative approach to model patterns of determinants associated with discontinuation of ET.METHODSPatients with nonmetastatic breast cancer receiving active adjuvant ET were approached by nurse practitioners to complete an anonymous survey at one time point. We simulated a prospective model by iteratively regressing adverse effects onto adherence status across windowed time periods of 2 to 3 consecutive years, bootstrapping the smaller group of nonadherent patients and subsampling the larger adherent group.RESULTSFrom February to April 2013, 216 participants were enrolled in the study. Forty patients (18.5%) reported that they had discontinued ET during the first 5 years of ET, and an additional four patients (1.9%) missed > 20% of their doses. Using two-sided significance tests, simulations showed that all 13 ET adverse effects and reasons for discontinuation were significantly related to discontinuation at some time point during ET. Worry about ET cost (odds ratio [OR], 1.79), emotional distress (OR, 1.72), and bone and joint pain (OR, 1.69) were the three most impactful reasons for discontinuation, with varying patterns of influence over time.CONCLUSIONThese analyses provide preliminary evidence that there are varying patterns of discontinuation of ET. Although some reasons for discontinuation exerted a steady influence over the 6-year ET trajectory (ie, bone and joint pain), other reasons, such as cost, cognitive complaints, and general dislike of pills, became more important in the later years of ET.

Highlights

Despite the proven efficacy of adjuvant endocrine treatment (ET), early discontinuation of ET is a problem
Some reasons for discontinuation exerted a steady influence over the 6-year ET trajectory, other reasons, such as cost, cognitive complaints, and general dislike of pills, became more important in the later years of ET
Using a 5-point Likert response scale ranging from “not at all” to “very much,” participants were asked to rate the impact of 13 ET adverse effects and concerns on the decision to discontinue ET: worry about bone loss, bone and joint pain, low sex drive, vaginal dryness, hot flashes, worry about drug interaction with other existing medication, insomnia or trouble sleeping, weight gain attributed to ET, emotional distress attributed to ET, cognitive dysfunction, forgetting to take endocrineblocking pill, cost of ET, and general dislike of taking medication

Summary

Introduction

Despite the proven efficacy of adjuvant endocrine treatment (ET), early discontinuation of ET is a problem. The majority of extant medication adherence literature includes classical regression analyses, calculating the odds of becoming nonadherent given a participant’s profile of descriptive patient, symptom, or treatment features at baseline. In their basic form at least, classical regression models do not effectively capture the varying effects of predictor variables on outcome over time.[10] data for these studies come primarily from secondary sources, such as insurance databases or clinical trials, the primary end point of which was disease-free survival

Methods

Results

Discussion

Conclusion