Agitation in Alzheimer's disease: Novel outcome measures reflecting the International Psychogeriatric Association (IPA) agitation criteria.

Introduction The 2017 European Union-North American Clinical Trials in Alzheimer's Disease Task Force recommended development of clinician-rated primary outcome measures for Alzheimer's disease (AD) agitation trials, incorporating International Psychogeriatric Association (IPA) criteria. Methods In a modified Delphi process, Cohen-Mansfield Agitation Inventory (CMAI) and Neuropsychiatric Inventory-Clinician (NPI-C) items were mapped to IPA agitation domains generating novel instruments, CMAI-IPA and NPI-C-IPA. Validation in the Agitation and Aggression AD Cohort (A3C) assessed minimal clinically important differences (MCIDs), change sensitivity, and predictive validity. Results MCID was -17 (odds ratio [OR] = 14.9, 95% confidence interval [CI] = 6.8-32.6) for CMAI; -5 (OR = 9.3, 95% CI = 4.0-21.2) for CMAI-IPA; -3 (OR = 11.9, 95% CI = 4.1-34.8) for NPI-C-A+A; and -5 (OR = 7.8, 95% CI = 3.4-17.9) for NPI-C-IPA at 3 months. Areas under the curve suggested no scale better predicted global clinician ratings. Sensitivity to change for all measures was high. Conclusion Internal consistency and reliability analyses demonstrated better accuracy for the NPI-C-IPA than for the CMAI-IPA and can be used for agitation clinical trial inclusion, and for response to intervention.