Implementation of decision aids in medical decision making is still low, partly because of fear that involving patients could have a negative impact. This study focuses on the effect of increasing patient involvement, by means of a decision aid, on regret in the context of the treatment choice for prostate cancer.
Method:
Between 2008 and 2011, patients with localized prostate cancer were individually randomized to 1) usual care (n=77) and 2) usual care plus a discussion on risks and benefits of different treatment options by means of a decision aid (N=163). The treatments options were radical prostatectomy, external beam radiotherapy and brachytherapy. This was a multicenter trial (3 sites) with imbalanced randomization (1:2). The primary outcome measure was regret, which was assessed before, and 6 and 12 months after treatment with the regret scale of Brehaut(1), and with three newly developed regret scales focusing on process regret, option regret and outcome regret. Additional information was gathered on patient characteristics, participation, knowledge, anxiety, healthy-related quality-of-life and decision evaluation.
Result:
The decision aid increased patient participation (P=0.002) and subjective knowledge (P=0.006). The effect of the decision aid was comparable on the three aspects of regret, but seemed to differ between patients with or without serious morbidity at 12 months. In patients with serious side effects, the use of a decision aid resulted in a trend to less option regret (P=0.075) and less Brehaut regret (P=0.061), with an effect size of 0.35 to 0.38, respectively.
Conclusion:
Our data suggest that the decision aid had little effect on regret in patients without serious side effects, but it may lead to less regret in patients with serious side effects.