Screening for Alzheimer’s Disease General Principles J.W. Ashford, University of Kentucky Veterans Affairs Medical Center Lexington AAGP – 3/3/03
Jan 16, 2016
Screening for Alzheimer’s DiseaseGeneral Principles
J.W. Ashford,
University of Kentucky
Veterans Affairs Medical Center
Lexington
AAGP – 3/3/03
Early Recognition of AD: Consensus Statement
(AAGP, AGS, Alzheimer’s Association)
AD continues to be missed as diagnosis
AD is unrecognized and under-reportedpatients do not realized families tend to compensate
Effective treatment and management techniques are available
Small et al., JAMA, 1997
Why Diagnose AD Early?Safety (driving, compliance, cooking, etc.)Family stress and misunderstanding (blame, denial) Early education of caregivers of how to handle patient (choices, getting started)Advance planning while patient is competent (will, proxy, power of attorney, advance directives)Patient’s and Family’s right to knowSpecific treatments now available May slow underlying disease process May delay nursing home placement longer if started
earlier
Importance of screening for Alzheimer’s disease
Early treatments may: Slow the course of the disease Delay nursing home placement Decrease the cost of the disease
Very early treatments may prevent dementia
What is the cost of testing versus the cost of not testing?
At what age is testing cost-effective?
U.S. Census 2000 by age
0
250,000
500,000
750,000
1,000,000
1,250,000
1,500,000
1,750,000
2,000,000
2,250,000
2,500,000
0 10 20 30 40 50 60 70 80 90 100
Age
# p
eo
ple
Males,138,053,563Females,143,368,343
Total = 281,421,906>60 = 45,809,291>65 = 35,003,844>85 = 4,251,678>100= 62,545
U.S. mortality by age - 1999
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,000
0 10 20 30 40 50 60 70 80 90 100
Age
Nu
mb
er
of
pe
op
le
Males, 1,175,460
Females, 1,215,939
U.S. mortality rate by age1999 CDC / 2000 census
0.0001
0.0010
0.0100
0.1000
1.0000
0 10 20 30 40 50 60 70 80 90 100
Age
prob
abi
lity
MalesFemalesdementia incidence
U.S. mortality rate by age1999 CDC / 2000 census
y = 9E-05e 0. 0848x
R 2 = 0.9974y = 3E-05e 0. 0926x
R 2 = 0.9973
0.0001
0.0010
0.0100
0.1000
1.0000
30 40 50 60 70 80 90 100
Age
pro
bability
Males, Td = 8.2 yrs
Females, Td = 7.5 yrs
Expon. (Males, Td =8.2 yrs)Expon. (Females, Td =7.5 yrs)
U.S. Dementia Incidence (4 million / 8yr)
02000400060008000
10000120001400016000
50 60 70 80 90 100
Age
# /
yr
male=170,603
female=329,115
Dementia incidence by individual
00.0020.0040.0060.0080.01
0.0120.0140.016
50 60 70 80 90 100
Age
Pro
po
rtio
na
l ris
k /
yr
male=34%
female=66%
Age Specific Dementia Rate
0.0001
0.001
0.01
0.1
1
50 60 70 80 90 100
Age (years)
Pro
ba
bili
ty /
yr
Factors Influencing Variation in Age of Onset
Genetics (especially APOE), family historyNeurological factors Stroke Brain injury
Medical factors Vascular disease Medications: NSAIDS, statins, female HRT
EducationGenderAgeism (more concern for younger individuals)
Age-Associated Memory Impairment(loss of memory without loss of social function)
vs
Mild Cognitive Impairment / Early Alzheimer
Memory declines with age At what point is memory abnormal?
Heisenbergian uncertainty – the earlier problem is, the less clearly defined it is.
How does age affect consideration of abnormality? Memory problems are more tolerated in older individuals
Older individuals remember more complex items and relationships
Older individuals are slower to respond
Estimate MMSE as a function of time
0
5
10
15
20
25
30
-10 -8 -6 -4 -2 0 2 4 6 8 10
Estimated years into illness
MM
SE
scor
e
AAMI / MCI DEMENTIA
ALZHEIMER’S DISEASE
Ashford et al., 1995
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Age
Perc
enta
ge AD
MCI
Non-Affected
Yesavage et al., 2002
BLT/Ashford Memory Test(to detect AD onset)
New test to screen patients for Alzheimer’s disease using the World-Wide Web – based testing
Test only takes 1-minute
Test can be repeated often (quarterly)
Any change over time can be detected
Test is at: www.ibaglobal.com/BLT
For info, see: www.medafile.com