A Two-Study Comparison of Clinical and MRI Markers of Transition from Mild Cognitive Impairment to Alzheimer’s Disease

Table 1

Baseline sample characteristics of patients with MCI with three years of followup.

Variables	Alzheimer’s Disease Neuroimaging Initiative (ADNI)				Questionable Dementia (QD) study
	Total 𝑁=282 %	Nonconverter 𝑁=125 %	Converter 𝑁=157 %	Group difference Chi-square; 𝑃 value	Total (𝑁=126); %	Not converted (𝑁=93); %	Converted to AD (𝑁=33) %	Group difference Chi-square 𝑃 value
Gender (% Male)	67.02	76.0	59.87	0.0063	26.19	48.39	39.39	0.3154
Race (%)
Caucasian	92.20	92.00	92.36	0.8913	75.40	77.42	69.70	0.8452
Hispanic	2.84	2.40	3.18		16.67	15.05	21.21
African; American	2.48	2.40	2.55		5.56	5.38	6.06
Other	2.48	3.20	1.91		2.40	2.15	3.03
ApoE ε4	56.03	40.00	68.35	<0.0001	27.27	25.27	33.33	0.5332
	Mean (SD)	Mean (SD)	Mean (SD)	𝑡-test	Mean (SD)	Mean (SD)	Mean (SD)	𝑡-test
Age (years)	74.59 (7.30)	74.63 (7.66)	74.56 (7.03)	0.9351	67.31 (9.72)	65.24 (9.69)	73.12 (7.21)	<0.0001
Education (years)	15.76 (2.88)	15.95 (2.81)	15.60 (2.94)	0.3074	15.18 (4.03)	15.58 (3.77)	14.06 (4.58)	0.0507
MMSE	27.08 (1.80)	27.62 (1.74)	26.66 (1.73)	<0.0001	27.52 (2.21)	28.02 (1.99)	26.12 (2.20)	<0.0001
AVLT/SRT	34.14 (10.90)	39.73 (12.16)	29.69 (7.16)	<0.0001	42.66 (9.49)	45.60 (8.26)	34.09 (7.50)	<0.0001
FAQ	2.84 (2.79)	1.61 (2.08)	3.82 (2.90)	<0.0001	1.69 (2.05)	1.28 (1.84)	2.73 (2.21)	0.0002
	𝑁=274	𝑁=120	𝑁=154	𝑡-test	𝑁=118	𝑁=89	𝑁=29	𝑡-test
Hippocampal volume	6.30 (1.10)	6.78 (1.01)	5.92 (1.02)	<0.0001	4.20 (0.73)	4.37 (0.62)	3.69 (0.74)	<0.0001
Entorhinal cortex volume	0.33 (0.08)	0.36 (0.07)	0.30 (0.07)	<0.0001	0.45 (0.10)	0.47 (0.09)	0.38 (0.09)	<0.0001
Intracranial volume	1580.79 (166.15)	1602.50 (152.48)	1563.69 (174.67)	0.0549	1306.60 (126.83)	1317.43 (128.55)	1273.71 (117.49)	0.0919

MMSE: Mini-Mental State Exam, AVLT: Auditory Verbal Learning Test (sum of 6 trials), SRT: Selective Reminding Task (sum of 6 trials), FAQ: Pfeffer’s Functional Activities Questionnaire (10 items), SD: standard deviation, AD: Alzheimer’s disease. Hippocampal, entorhinal, and intracranial volumes are in cubic centimeters. Entorhinal cortex volumes measured in cubic millimeters in ADNI were converted to cubic centimeters. Intracranial volume in ADNI covered all intracranial structures including the cerebellum, but intracranial volume in QD was restricted to supratentorial intracranial volume.