Health-related quality of life factors associated with completion of a study delivering lifestyle exercise intervention for endometrial cancer survivors.

Purpose: The aim of this study was to examine associations between participants' quality of life and study completion. This is a secondary analysis of an exercise intervention study for endometrial cancer survivors.
Methods: We considered data for one-hundred post-treatment endometrial cancer survivors from a single-arm, six-month longitudinal exercise study. Participants received a home-based intervention consisting of exercise recommendations and telephone counseling sessions to encourage adherence. In addition to monitoring adherence to physical exercise recommendations, participants completed multiple psychological assessments, including health-related quality of life. Associations between study completion and health-related quality of life factors were analyzed using generalized additive models, to allow for possibly nonlinear associations.
Results: Measures of bodily pain contributed to the odds of study completion in a nonlinear way (p = 0.025), suggesting that improvements in these factors were associated with study completion, especially for individuals reporting very high levels of pain. In addition, association between participants' levels of anxiety and study completion showed an inverse U-shaped relation: Whereas increase in anxiety was associated with higher odds of completion for individuals with low anxiety score (0-4), increase in anxiety contributed to lower odds of study completion for individuals with anxiety scores of approximately 5-10 (p = 0.035).
Conclusions: Results from this study indicate that baseline health-related quality of life factors may be associated with study completion in exercise intervention studies. In order to increase study completion rates, individually tailored study strategies may be prepared based on the baseline quality of life responses.