Purpose: To examine changes in anxiety over time (trajectories) in men with prostate cancer faced with a decision to participate in a clinical trial and to identify demographic and study variables that predict these trajectories.
Methods: Our data come from a larger study examining the efficacy of a decision aid on decisional conflict in men with prostate cancer who were deciding whether to participate in a prostate cancer clinical trial. We used latent growth mixture models to identify 'classes' (i.e. groups) of participants with different trajectories of anxiety, as assessed by the State-Trait Anxiety Inventory state scale, and binary logistic regression to determine predictors of anxiety 'class'.
Results: In 128 men with prostate cancer (mean age = 63), growth mixture modelling identified two classes defined by different anxiety trajectories. One class (n = 27) started with a higher mean anxiety score and did not change over time (stable high), whereas the second class (n = 101) started with lower anxiety and significantly reduced over time (low and recovering). None of the demographic and study variables (including age, education, marital status, and decision to join the trial) was predictive of anxiety class.
Conclusions: Men treated for prostate cancer who have high levels of anxiety after surgery may continue to have persistent high anxiety levels which do not reduce naturally over time. Patient or disease characteristics do not appear to predict anxiety. It is important, therefore, to monitor for anxiety in this population and refer for psychological interventions where required.
Keywords: Anxiety; Latent growth mixture model; Patient decision-making; Prostate cancer; Trajectories.