Epilepsy in the Elderly: Risk factors as Targets for Prevention?

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Epilepsy in the Elderly Risk factors as Targets
for Prevention?
Mary Jo V. Pugh, PhD, RN
This study is funded by VA Health Services
Research and Development Service (IIR 02-274)
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Collaborators

• Dan R. Berlowitz, MD, MPH
• Janice Knoefel, MD
• Joyce Cramer, BS
• Omotola Hope, MD
• Anne VanCott, MD
• Eric Mortensen MD, MSc
• And the TIGER Research Team

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Background

• Epilepsy is one of the most common chronic
  neurological diseases
• Incidence of epilepsy is highest in the elderly

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Incidence of Epilepsy
Rochester, Minn 1935-84Hauser, Epilepsia, 33
1992
200
Male
Female
150
Total
100
Incidence / 100,000
50
0
1
5
10
15
20
30
40
50
60
70
80
Age
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Aging in America Implications for Epilepsy

• Now30 of new cases are elderly
• 202050 of new cases will be elderly

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Why Try to Prevent Epilepsy in the Elderly?

• Epilepsy is associated with high costs
• Lifetime cost per patient (1990 dollars)
• 4,272 remission after initial diagnosis and
  treatment
• 138,602 for persons with intractable and
  frequent seizures (30-40 of epilepsy
  population).
• Begley et al.1994, Epilepsia
• Epilepsy in the elderly affects HRQoL
• Affects both physical and mental aspects

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HRQoL in Older Veterans
Scale Epilepsy Status Adjusted Score
Physical Function No Epilepsy 43.85 (0.25)
Chronic Epilepsy 39.32 (0.48)
New Epilepsy 34.80 (1.41)

Mental Health No Epilepsy 68.77 (0.19)
Chronic Epilepsy 64.79 (0.36)
New Epilepsy 61.50 (1.05)
Controlling for physical and mental
comorbidities defined by Selim et al. 2004 Pugh
et al. 2007 International Review of Neurobiology
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Purpose

• Identify risk factors for new-onset epilepsy in
  older patients
• Risk factors may then be evaluated as targets for
  prevention or delay of epilepsy onset in older
  patients

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Data Sources

• VA National Patient Care Database (FY 99-FY00)
• Medicare Data procured by Veterans Information
  Resource Center (FY 99-FY00)
• Used only to identify individuals with
  epilepsynot available for non-epilepsy patients
• VA National Pharmacy Benefits Management Database
  (FY 99-00)

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Methods

• Population
• Veterans gt65 years old
• Received at least on drug from VA in FY00
• Received VA care in FY99 FY00
• Dependent Variable New Onset Epilepsy
• First diagnosis of epilepsy based on ICD-9-CM
  Code (780.39 convulsion 345 epilepsy)
• Treatment with anti-epileptic drug
• No indication of epilepsy Geriatric Cohort
• Compared Risk Factors in Epilepsy Cohort and
  Geriatric Cohort

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CHARACTERISTICS IDENTIFIED IN VA DATABASES

• DEMOGRAPHIC
• Age, Sex , Race
• CNS DISORDERS
• Cerebrovascular Disease
• Dementia
• Brain Tumor
• Recent Serious Head Injury
• Other Neurological Diseases (e.g. MS, Parkinson's
  Disease)

• SYSTEMIC DISORDERS
• Cardiovascular Disease
• Peripheral Vascular Disease
• Hypertension
• Diabetes
• Obesity
• Hypercholesterolemia

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RESULTS DEMOGRAPHIC VARIABLES
New Onset Epilepsy N1,843 Geriatric Cohort N1,023,376
65-74 yrs 74-75 yrs 85 yrs 52 (n966) 44 (n818) 3 (n3) 55 (n558,661) 42 (n430,125) 3 (n34,590)
Men Women 98 (n1,813) 2 (n30) 98 (n1,002,806) 2 (n20,507)
Black White Hispanic Other/Unknown 18 (n324) 65 (n1,204) 5 (n83) 12 (n232) 9 (n92,662) 67 (n683,615) 4 (n44,619) 20 (n36,842)
plt .001
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RESULTS NEUROLOGICAL RISK FACTORS
New Onset Epilepsy N1,843 Geriatric Cohort N1,023,376
Stroke 40 (n700) 15 (n151,971)
Dementia 16 (n308) 7 (n67,236)
Brain Tumor 2 (n29) 0.6 (n5,833)
Other CNS Disorders 9 (n160) 4 (n36,842)
plt .001
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SYSTEMIC VASCULAR RISK FACTORS
New Onset Epilepsy N1,843 Geriatric Cohort N1,023,376
Cardiovascular Disease 37 (n674) 30 (n312,334)
Peripheral Vascular Disease 20 (n363) 16 (n164,150)
Hypertension 75 (n1,389) 72 (n734,477)
Diabetes 31 (n566) 30 (n301,487)
Obesity 10 (n181) 13 (n137,542)
Hyperlipidemia 34 (n683) 42 (n434,628)
plt .001
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LOGISTIC REGRESSION CNS Risk Factors For
New-Onset Geriatric Epilepsy
ODDS RATIO 95 CI
Cerebrovascular Disease 3.08 2.77-3.41
Dementia 1.64 1.44-1.88
Recent Serious Head Trauma 2.05 1.39-3.04
Brain Tumor 2.18 1.51-3.16
Other CNS Disorders 1.54 1.30-1.82
Controlling for demographic and systemic disease
characteristics
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LOGISTIC REGRESSION Systemic Risk Factors For
New-Onset Geriatric Epilepsy
ODDS RATIO 95 CI
Cardiovascular Disease 1.11 1.00-1.22
Peripheral Vascular Disease 1.05 0.95-1.18
Hypertension 0.94 0.83-1.06
Diabetes 0.98 0.89-1.09
Obesity 0.75 0.64-0.87
Hyperlipidemia 0.90 0.80-1.02
Controlling for demographic and neurological risk
factors
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LOGISTIC REGRESSION Lipid Lowering Drug Use
ODDS RATIO 95 CI
Lipid lowering drugs STATINS 0.64 0.56-0.73
Lipid lowering drugs OTHER 0.82 0.61-1.10
Controlling for demographic, neurological and
systemic risk factors
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LIMITATIONS

• Use of administrative data to identify study
  cohorts
• Chart abstraction validation confirmed that
  new-onset epilepsy was accurately identified
  using our algorithm
• Diagnosis of obesity based on ICD 9 codes
• Statin use based on pharmacy data
• Healthy User Effect?
• Did not use Medicare data for identifying
  comorbid conditions.
• May be underestimates

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CONCLUSIONS

• Consistent with previous research stroke was the
  strongest risk factor for new-onset epilepsy in
  older patients
• Systemic risk factors were not associated with an
  independent risk
• Association of systemic risk factors may work
  indirectly through increased risk for stroke and
  dementia in older men
• Potential protective mechanism of statins may be
  due to reduced risk for stroke.

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Impact

• Use of statins for primary prevention of
  myocardial infarction and stroke may have
  additional benefits by reducing risk of epilepsy.
  
• Prevention of epilepsy will benefit both the
  healthcare system and the patient.

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Thank You!

• Contact Information
• Mary Jo V. Pugh PhD, RN
• pughm_at_uthscsa.edu