Analysis of the Relationship of Cognitive Impairment and Functional Impairment in Mild Alzheimer's Disease in EXPEDITION 3.

BACKGROUND

Clinical progression of Alzheimer's disease is characterized by impairment in cognition and function.

OBJECTIVE

To assess the relationship between cognitive and functional impairment in mild Alzheimer's disease.

DESIGN

Spearman's rank correlations between cognitive and functional measures were calculated. Autoregressive cross-lagged panel analyses were used to determine the temporal relationship between cognitive and functional decline.

SETTING

Post-hoc analysis of clinical trial data.

PARTICIPANTS

Placebo-treated patients with mild Alzheimer's disease from the Phase 3 solanezumab study EXPEDITION 3.

INTERVENTION

Placebo.

MEASUREMENTS

Cognitive and functional measures were assessed at baseline and at six post-baseline time points through Week 80.

RESULTS

Correlation between cognitive and functional measures was 0.41 at baseline and 0.65 at Week 80. Autoregressive cross-lagged panel analysis demonstrated that cognitive impairment preceded and predicted subsequent functional decline, but functional scores did not predict cognitive outcomes.

CONCLUSIONS

This study supports the hypothesis that functional impairment predictably follows cognitive decline in mild Alzheimer's disease dementia.