Characteristics of Subjects.

<p>Characteristics of Subjects.</p

Life expectancy estimations using survival curve models and validation cohorts.

<p>Life expectancy estimations using survival curve models and validation cohorts.</p

Factors Associated with Conversion from Amnestic MCI to AD^*.

<p>AD, Alzheimer's disease; ADAS-cog, Alzheimer's Disease Assessment Scale – cognitive subscale; CI, confidence interval; MCI, mild cognitive impairment.</p><p>*Only factors retained in the final model are included.</p><p>Factors Associated with Conversion from Amnestic MCI to AD^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113535#nt103" target="_blank">*</a>}.</p

Observed versus Predicted Conversion from Amnestic MCI to AD over 3 Years by Brief Clinical Index Point Score.

<p>The solid line shows the proportion of subjects predicted to progress from amnestic mild cognitive impairment (MCI) to probable Alzheimer's disease (AD) over three years as function of their brief clinical index point score, while the dotted line shows the actual proportions that progressed at each point score value based on three-year Kaplan-Meier (KM) estimates. The vertical bars show the number of individuals at each point score value (right vertical axis).</p

A Clinical Index to Predict Progression from Mild Cognitive Impairment to Dementia Due to Alzheimer's Disease

<div><p>Background</p><p>Mild cognitive impairment is often a precursor to dementia due to Alzheimer's disease, but many patients with mild cognitive impairment never develop dementia. New diagnostic criteria may lead to more patients receiving a diagnosis of mild cognitive impairment.</p><p>Objective</p><p>To develop a prediction index for the 3-year risk of progression from mild cognitive impairment to dementia relying only on information that can be readily obtained in most clinical settings.</p><p>Design and Participants</p><p>382 participants diagnosed with amnestic mild cognitive impairment enrolled in the Alzheimer's Disease Neuroimaging Initiative (ADNI), a multi-site, longitudinal, observational study.</p><p>Main Predictors Measures</p><p>Demographics, comorbid conditions, caregiver report of participant symptoms and function, and participant performance on individual items from basic neuropsychological scales.</p><p>Main Outcome Measure</p><p>Progression to probable Alzheimer's disease.</p><p>Key Results</p><p>Subjects had a mean (SD) age of 75 (7) years and 43% progressed to probable Alzheimer's disease within 3 years. Important independent predictors of progression included being female, resisting help, becoming upset when separated from caregiver, difficulty shopping alone, forgetting appointments, number of words recalled from a 10-word list, orientation and difficulty drawing a clock. The final point score could range from 0 to 16 (mean [SD]: 4.2 [2.9]). The optimism-corrected Harrell's c-statistic was 0.71(95% CI: 0.68–0.75). Fourteen percent of subjects with low risk scores (0–2 points, n = 124) converted to probable Alzheimer's disease over 3 years, compared to 51% of those with moderate risk scores (3–8 points, n = 223) and 91% of those with high risk scores (9–16 points, n = 35).</p><p>Conclusions</p><p>An index using factors that can be obtained in most clinical settings can predict progression from amnestic mild cognitive impairment to probable Alzheimer's disease and may help clinicians differentiate between mild cognitive impairment patients at low vs. high risk of progression.</p></div

Baseline Characteristics of 382 Participants with Amnestic Mild Cognitive Impairment (MCI).

<p>Table includes selected demographic and medical history variables and all items from within each domain that were associated with conversion to AD (p<0.20). AD, Alzheimer's disease; ADAS-Cog, Alzheimer's Disease Assessment Scale – cognitive subscale; FAQ, Functional Assessment Questionnaire; NPI, Neuropsychiatric Inventory; SD, standard deviation. Data missing as follows: Blood pressure (4), pulse (1), FAQ (3).</p><p>Baseline Characteristics of 382 Participants with Amnestic Mild Cognitive Impairment (MCI).</p

Comparison of the Full and Brief Clinical AD Prediction Indexes.

<p>The predicted (solid lines) and observed (dashed lines) are shown as a function of risk score values based on the previously published full index (light grey lines) and brief clinical index (dark grey lines). Prognostic accuracy was significantly higher for the full index (optimism corrected Harrell's c, 0.74) than the brief clinical index (0.71). However, the plot shows good concordance between observed and predicted risk for both indices.</p

Proportion of Subjects with Amnestic MCI Who Converted to AD in Low, Medium and High Risk Groups.

<p>Fourteen percent of subjects with low risk scores (upper line, 0–2 points, n = 124) progressed from amnestic MCI to AD over three years compared to 51% of those with moderate risk scores (middle line, 3–8 points, n = 223) and 91% of those with high risk scores (lower line, 9–16 points, n = 35).</p