DEVELOPMENT AND VALIDATION OF A DECISION BURDEN SCALE

Purpose: To develop and validate an instrument measuring patients’ perceived burden from treatment decision-making, in terms of everyday behavior and emotions.

Method: Thurstone’s three-step method of equal appearing intervals was applied to develop a “Decision Burden Scale” (DBS). First, asymptomatic abdominal aortic aneurysm patients and healthy volunteers in a university hospital were asked which behavior people might display, or emotions they might experience in daily life, when facing a major treatment decision. Similar statements were grouped. From each, one representative statement was selected, for example: “I would discuss this with friends or family”. Second, another group of aneurysm patients and healthy volunteers judged each statement’s level of decisional burden on a scale from 0-10. The final scale was composed of statements with unambiguous rankings only. Third, a new sample of aneurysm patients, who were about to decide on whether to undergo elective surgery, completed the DBS, Decisional Conflict Scale, anxiety items of the Hospital Anxiety and Depression Scale, and chose their preferred treatment option. Internal consistency of the DBS was determined by assessing Cronbach’s alpha. Convergent validity was measured by correlating DBS with the construct of decisional conflict, which were purported to correlate substantially. Anxiety was hypothesized to slightly correlate to decisional burden. Known-groups approach was performed by comparing DBS-scores of patients with a strong treatment preference versus uncertain patients.

Result: Twenty-nine healthy volunteers and 31 aneurysm patients generated 363 statements on decisional burden. From these, 28 unique and representative items were derived. These items were presented to 42 healthy volunteers and 37 aneurysm patients. After their judgment, five items were eliminated due to lack of agreement. This set was answered by 25 aneurysm patients deciding about elective surgery. Cronbach’s alpha was 0.75 after elimination of four more items. Decision burden did not correlate with decisional conflict (r=0.33, p=0.15), but did correlate with the construct of anxiety (r=0.63, p=0.001). DBS scores of patients with a strong treatment preference did not differ significantly from uncertain patients (p=0.89).

Conclusion: A 19-item DBS with satisfying internal consistency could be developed in aneurysm patients. However, decision burden experienced in daily life was related to the concept of anxiety rather than to decision conflict.