Cognitive change in donepezil treated patients with vascular or mixed dementia.
BACKGROUND
vascular dementia (VaD) and mixed Alzheimer's disease (AD/VaD) are common. How best to monitor treatment is not clear. Our objective was to compare responsiveness and construct validity of change scores, following donepezil treatment, of the standardized Mini-Mental State Examination (sMMSE) and other measures potentially usable in primary care.


METHODS
A six-month, outcome measurement study. The Disability Assessment for Dementia (DAD), CLOX-1 and 2, Phonetic Fluency, a short Neuropsychiatric Inventory, (the NPI-Q), Clinical Global Impression (CGI) and the SymptomGuide™ (SG) were measured. Construct validity was tested by correlating change scores, and responsiveness by calculating standardized response means (SRMs).


RESULTS
Of 148 treated patients, 116 completed. The mean sMMSE increased by 0.7 (95% Confidence Interval (CI) = -0.005, 1.41; p=0.06; SRM= 0.15). There was no statistically significant difference in the DAD. The NPI-Q (-1.4; 95% CI = -2.08, -0.72; p<0.01; SRM=0.24), CLOX-1 (0.9; 95% CI = 0.19, 1.61; p<0.01; SRM=0.21), CLOX-2 (0.9; 95% CI = 0.17, 1.63; p=0.03; SRM=0.26), Phonetic Fluency (0.9; 95% CI = 0.19, 1.61; p=0.02; SRM=0.21) and SG (0.35; 95% CI = 0.20,0.51; p<0.01; SRM=0.28) each detected significant improvement. The CGI suggested improvement in 74 completers (64%) - mostly "minimal" (44/116, 38%) - while 21/116 (18%) were worse. Change scores at 24 weeks were at best modestly correlated with each other (range -0.22 to 0.30).


DISCUSSION
Different measures showed different responsiveness, in a setting in which the mean treatment effect seems to have been small, but clinically detectable. Patient-centered and executive function measures might be useful in vascular and mixed dementia.