Time course of arthralgia among women initiating aromatase inhibitor therapy and a postmenopausal comparison group in a prospective cohort

Abstract

Background: More than 80,000 postmenopausal breast cancer patients in the United States each year are estimated to begin a 5-year course of aromatase inhibitors (AIs) to prevent recurrence. AI-related arthralgia (joint pain and/or stiffness) may contribute to nonadherence, but longitudinal data are needed on arthralgia risk factors, trajectories, and background in postmenopause. This study sought to describe 1-year arthralgia trajectories and baseline covariates among patients with AI and a postmenopausal comparison group.

Methods: Patients initiating AIs (n = 91) were surveyed at the time of AI initiation and at 6 repeated assessments over 1 year. A comparison group of postmenopausal women without breast cancer (n = 177) completed concomitantly timed surveys. Numeric rating scales (0-10) were used to measure pain in 8 joint pair groups (bilateral fingers, wrists, elbows, shoulders, hips, knees, ankles, and toes). Poisson regression models were used to analyze arthralgia trajectories and risk factors.

Results: By week 6, the AI-initiating group had more severe arthralgia than did the comparison group (ratio of means = 1.8, 95% confidence interval = 1.24-2.7, P = .002), adjusting for baseline characteristics. Arthralgia then worsened further over 1 year in the AI group. Menopausal symptom severity and existing joint-related comorbidity at baseline among women initiating AI were associated with more severe arthralgia over time.

Conclusions: Patients initiating AI should be told about the timing of arthralgia over the first year of therapy, and advised that it does not appear to resolve over the course of a year. Menopausal symptoms and joint-related comorbidity at AI initiation can help identify patients at risk for developing AI-related arthralgia.

Trial registration: ClinicalTrials.gov NCT00954564.

Copyright © 2013 American Cancer Society.

Figures

Figure 1

Cohort screening and enrollment flow chart

Figure 2

Model-based mean composite arthralgia severity score by week and group, adjusted to medians and modes of numeric and categorical covariates, respectively