The Quick Mild Cognitive Impairment screen correlated with the Standardized Alzheimer's Disease Assessment Scale–cognitive section in clinical trials

OBJECTIVES: The Alzheimer's Disease Assessment Scale-cognitive section and its standardized version (SADAS-cog) are the current standard for assessing cognitive outcomes in clinical trials of dementia. This study compares a shorter cognitive instrument, the Quick Mild Cognitive Impairment (Qmci) screen, with the SADAS-cog as outcome measures in clinical trials. STUDY DESIGN AND SETTING: The SADAS-cog, Qmci, Clinical Dementia Rating (CDR) scale, and the Lawton-Brady activities of daily living (ADL) scale were assessed at multiple time points, over 1 year in a multicenter randomized clinical trial of 406 patients with mild to moderate Alzheimer's dementia. Correlations were estimated using regression at each time point, all time points, and mean values across time. Responsiveness was assessed using the standardized response mean (SRM). RESULTS: Regression for pooled time points showed strong and significant correlation between the SADAS-cog and Qmci (r = -0.75, P < 0.001). Correlations remained strong for mean values across time and at each time point. The SADAS-cog and Qmci also correlated with CDR and ADL scores. There was no difference in SRMs between the SADAS-cog and Qmci [t(357) = -0.32, P = 0.75]. CONCLUSION: The Qmci correlated strongly with the SADAS-cog and both were equally responsive to deterioration. We suggest that clinicians and investigators can substitute the shorter Qmci for the SADAS-cog.