Association between clinical dementia rating and clinical outcomes in Alzheimer's disease

INTRODUCTION: We examined associations between the Clinical Dementia Rating Scale (CDR) and function (Functional Assessment Scale [FAS]), neuropsychiatric symptoms (Neuropsychiatric Inventory Questionnaire [NPI-Q]), and cognitive impairment in Alzheimer's disease (AD).METHODS: We used data from the National Alzheimer's Coordinating Center Uniform Data Set and defined cognitively unimpaired and AD stages using CDR-global.RESULTS: Functional and neuropsychiatric symptoms occur as early as the mild cognitive impairment (MCI) phase. The adjusted lest square mean FAS (95% confidence interval [CI]) was lowest in cognitively unimpaired (3.88 [3.66, 4.11] to 5.01 [4.76, 5.26]) and higher with more advanced AD (MCI: 8.17 [6.92, 9.43] to 20.87 [19.53, 22.20]; mild: 18.54 [17.57, 19.50] to 28.13 [27.14, 29.12]; moderate: 26.01 [25.31, 26.70] to 29.42 [28.73, 30.10]). FAS and NPI-Q scores increased steeply with MCI (NPI-Q: 5.55 [4.89, 6.20] to 7.11 [6.43, 7.78]) and mild AD dementia (NPI-Q: 6.66 [5.72, 7.60] to 8.32 [7.32, 9.33]).DISCUSSION: CDR-global staged AD by capturing differences in relevant outcomes along AD progression.