Context: Optimal treatment to postpone functional decline in patients with dementia is not established.

Objective: To test a nonpharmacologic intervention realigning environmental demands with patient capabilities.

Design, setting, and participants: Prospective 2-group randomized trial (Care of Persons with Dementia in their Environments [COPE]) involving patients with dementia and family caregivers (community-living dyads) recruited from March 2006 through June 2008 in Pennsylvania.

Interventions: Up to 12 home or telephone contacts over 4 months by health professionals who assessed patient capabilities and deficits; obtained blood and urine samples; and trained families in home safety, simplifying tasks, and stress reduction. Control group caregivers received 3 telephone calls and educational materials.

Main outcome measures: Functional dependence, quality of life, frequency of agitated behaviors, and engagement for patients and well-being, confidence using activities, and perceived benefits for caregivers at 4 months.

Results: Of 284 dyads screened, 270 (95%) were eligible and 237 (88%) randomized. Data were collected from 209 dyads (88%) at 4 months and 173 (73%) at 9 months. At 4 months, compared with controls, COPE patients had less functional dependence (adjusted mean difference, 0.24; 95% CI, 0.03-0.44; P = .02; Cohen d = 0.21) and less dependence in instrumental activities of daily living (adjusted mean difference, 0.32; 95% CI, 0.09-0.55; P = .007; Cohen d = 0.43), measured by a 15-item scale modeled after the Functional Independence Measure; COPE patients also had improved engagement (adjusted mean difference, 0.12; 95% CI, 0.07-0.22; P = .03; Cohen d = 0.26), measured by a 5-item scale. COPE caregivers improved in their well-being (adjusted mean difference in Perceived Change Index, 0.22; 95% CI, 0.08-0.36; P = .002; Cohen d = 0.30) and confidence using activities (adjusted mean difference, 0.81; 95% CI, 0.30-1.32; P = .002; Cohen d = 0.54), measured by a 5-item scale. By 4 months, 64 COPE dyads (62.7%) vs 48 control group dyads (44.9%) eliminated 1 or more caregiver-identified problems (chi(2/1) = 6.72, P = . 01).

Conclusion: Among community-living dyads, a nonpharmacologic biobehavioral environmental intervention compared with control resulted in better outcomes for COPE dyads at 4 months. Although no group differences were observed at 9 months for patients, COPE caregivers perceived greater benefits.

Trial registration: clinicaltrials.gov Identifier: NCT00259454.