Alzheimer's disease patients' and caregivers' capacity, competency, and reasons to enroll in an early-phase Alzheimer's disease clinical trial.

OBJECTIVES

To examine the capacity, competency, and reasons for enrolling of patients with Alzheimer's disease (AD) and of their caregivers in an early phase AD clinical trial.

DESIGN

Interviews were conducted with patients with AD, nondemented older persons, and caregivers.

SETTING

Participants' homes.

PARTICIPANTS

Fifteen patients with mild to moderate AD, 15 age- and education-matched nondemented older persons, and 15 patient caregivers.

MEASUREMENTS

Capacity was measured using the MacArthur Competency Assessment Tool for Clinical Research (MacCAT-CR); a study coordinator who reviewed audiotapes of the capacity interviews judged competency, and the reasons for a decision were determined by coding the capacity interviews.

RESULTS

On all measures except the ability to make a choice, patients performed worse than controls (understanding: z = 3.2, P =.001; appreciation: z = 2.8, P =.005; reasoning: z = 3.5, P =.0005), and caregivers (understanding: z = 3.8, P =.0002; appreciation: z = 3.0, P =.003; reasoning: z = 3.6, P =.0003). Using the controls' performance to set psychometric criteria to define capacity, the proportions of patients with adequate understanding, appreciation, and reasoning were six of 15 (40%), three of 15 (20%), and five of 15 (33%). All caregivers and nine of the 15 (60%) patients were competent. Reasons for enrolling typically featured the potential benefit to the patients' health or well-being and altruism that was expressed as a desire to help other patients and their families or a desire to contribute to scientific knowledge.

CONCLUSIONS

The MacCAT-CR, in particular its understanding scale, is a reliable and valid way to assess patient capacity and competency to enroll in an early-phase clinical trial. Although many patients have significant impairments in their capacity, some mild-stage patients are competent. Reasons for enrolling in an early-phase trial blend an expectation of therapeutic benefit and a desire to help others.