Epilepsy in the Epilepsy in the Elderly: Risk factors Elderly: Risk factors

as Targets for as Targets for Prevention?Prevention?

This study is funded by VA Health Services Research and Development Service (IIR 02-274)

Mary Jo V. Pugh, PhD, RN

CollaboratorsCollaborators

• 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

BackgroundBackground

• Epilepsy is one of the most common chronic neurological diseases

• Incidence of epilepsy is highest in the elderly

Incidence of EpilepsyIncidence of EpilepsyRochester, Minn 1935-84

Hauser, Epilepsia, 33: 1992

1 5 10

15

20

30

40

50

60

70

80

Age

0

50

100

150

200 Mal

eFemaleTotal

Incidence / 100,000

Aging in America: Implications for Aging in America: Implications for EpilepsyEpilepsy

• Now—30% of new cases are elderly

• 2020—50% of new cases will be elderly

0

10

20

30

40

50

60

70

80

90

10 30 40 50 60 70 80

Why Try to Prevent Epilepsy in the Why Try to Prevent Epilepsy in the Elderly?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

HRQoL in Older VeteransHRQoL in Older VeteransScale 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

PurposePurpose

• 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

Data SourcesData 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 epilepsy—not available for non-epilepsy patients

• VA National Pharmacy Benefits Management Database (FY 99-00)

MethodsMethods• PopulationPopulation

– Veterans >65 years old Veterans >65 years old – Received at least on drug from VA in FY00Received at least on drug from VA in FY00– Received VA care in FY99 & FY00Received VA care in FY99 & FY00

• Dependent Variable: Dependent Variable: New Onset Epilepsy Onset Epilepsy•First diagnosis of epilepsy based on ICD-9-First diagnosis of epilepsy based on ICD-9-CM Code (780.39 convulsion; 345 CM Code (780.39 convulsion; 345 epilepsy)epilepsy)

•Treatment with anti-epileptic drugTreatment with anti-epileptic drug– No indication of epilepsy= Geriatric No indication of epilepsy= Geriatric

CohortCohort• Compared Risk Factors in Epilepsy Compared Risk Factors in Epilepsy

Cohort and Geriatric CohortCohort and Geriatric Cohort

CHARACTERISTICS CHARACTERISTICS IDENTIFIED IN VA IDENTIFIED IN VA

DATABASESDATABASES• DEMOGRAPHICDEMOGRAPHIC

– Age, Sex , RaceAge, Sex , Race

• CNS DISORDERSCNS DISORDERS– Cerebrovascular Disease– Dementia– Brain Tumor– Recent Serious Head

Injury– Other Neurological

Diseases (e.g. MS, Parkinson's Disease)

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

RESULTS: DEMOGRAPHIC RESULTS: DEMOGRAPHIC VARIABLESVARIABLES

New Onset EpilepsyNew Onset Epilepsy

N=1,843N=1,843

Geriatric CohortGeriatric Cohort

N=1,023,376N=1,023,376

65-74 yrs65-74 yrs

74-75 yrs74-75 yrs

85+ yrs85+ yrs

52% (n=966)52% (n=966)

44% (n=818)44% (n=818)

3% (n=3)3% (n=3)

55% (n=558,661)55% (n=558,661)

42% (n=430,125)42% (n=430,125)

3% (n=34,590)3% (n=34,590)

MenMen

WomenWomen

98% (n=1,813)98% (n=1,813)

2% (n=30)2% (n=30)

98% (n=1,002,806)98% (n=1,002,806)

2% (n=20,507)2% (n=20,507)

BlackBlack** **

WhiteWhite

HispanicHispanic

Other/UnknownOther/Unknown

18%18% (n=324) (n=324)****

65% (n=1,204)65% (n=1,204)

5% (n=83)5% (n=83)

12%12% (n=232) (n=232)

9%9% (n=92,662) (n=92,662)****

67% (n=683,615)67% (n=683,615)

4% (n=44,619)4% (n=44,619)

20%20% (n=36,842) (n=36,842)

** ** p< .001p< .001

RESULTS: NEUROLOGICAL RESULTS: NEUROLOGICAL RISK FACTORSRISK FACTORSNew Onset EpilepsyNew Onset Epilepsy

N=1,843N=1,843

Geriatric CohortGeriatric Cohort

N=1,023,376N=1,023,376

Stroke Stroke **** 40%40% (n=700) (n=700) 15% (n=151,971)15% (n=151,971)

Dementia Dementia **** 16%16% (n=308) (n=308)

7% (n=67,236)7% (n=67,236)

Brain Tumor Brain Tumor **** 2%2% (n=29) (n=29) 0.6% (n=5,833)0.6% (n=5,833)

Other CNS Other CNS

Disorders Disorders **** 9%9% (n=160) (n=160) 4% (n=36,842)4% (n=36,842)

** ** p< .001p< .001

SYSTEMIC VASCULAR SYSTEMIC VASCULAR RISK FACTORSRISK FACTORS

New Onset EpilepsyNew Onset Epilepsy

N=1,843N=1,843

Geriatric CohortGeriatric Cohort

N=1,023,376N=1,023,376

CardiovascularCardiovascular

Disease Disease ****37%37% (n=674) (n=674) 30% (n=312,334)30% (n=312,334)

Peripheral Peripheral **** Vascular Disease Vascular Disease

20%20% (n=363) (n=363)

16% (n=164,150)16% (n=164,150)

Hypertension Hypertension **** 75%75% (n=1,389) (n=1,389) 72% (n=734,477)72% (n=734,477)

DiabetesDiabetes 31% (n=566)31% (n=566) 30% (n=301,487)30% (n=301,487)

Obesity Obesity **** 10% (n=181)10% (n=181) 13%13% (n=137,542) (n=137,542)

Hyperlipidemia Hyperlipidemia **** 34% (n=683)34% (n=683) 42%42% (n=434,628) (n=434,628)

** ** p< .001p< .001

LOGISTIC REGRESSION: CNS Risk LOGISTIC REGRESSION: CNS Risk Factors For New-Onset Geriatric Factors For New-Onset Geriatric

EpilepsyEpilepsyODDS ODDS RATIORATIO

95% CI95% CI

Cerebrovascular DiseaseCerebrovascular Disease 3.083.08 2.77-3.412.77-3.41

DementiaDementia 1.641.64 1.44-1.881.44-1.88

Recent Serious Head TraumaRecent Serious Head Trauma 2.052.05 1.39-3.041.39-3.04

Brain TumorBrain Tumor 2.182.18 1.51-3.161.51-3.16

Other CNS DisordersOther CNS Disorders 1.541.54 1.30-1.821.30-1.82

Controlling for demographic and systemic disease characteristics

LOGISTIC REGRESSION: Systemic Risk LOGISTIC REGRESSION: Systemic Risk Factors For New-Onset Geriatric Factors For New-Onset Geriatric

EpilepsyEpilepsy

ODDS RATIOODDS RATIO 95% CI95% CI

CardiovascularCardiovascular

DiseaseDisease

1.111.11 1.00-1.221.00-1.22

Peripheral Vascular DiseasePeripheral Vascular Disease 1.05 1.05 0.95-1.18 0.95-1.18

Hypertension Hypertension 0.940.94 0.83-1.060.83-1.06

DiabetesDiabetes 0.980.98 0.89-1.090.89-1.09

Obesity Obesity 0.750.75 0.64-0.870.64-0.87

Hyperlipidemia Hyperlipidemia 0.900.90 0.80-1.020.80-1.02

Controlling for demographic and neurological risk factors

LOGISTIC REGRESSION: Lipid LOGISTIC REGRESSION: Lipid Lowering Drug UseLowering Drug Use

ODDS RATIOODDS RATIO 95% CI95% CI

Lipid lowering Lipid lowering

drugs: drugs: STATINSSTATINS0.640.64 0.56-0.730.56-0.73

Lipid lowering Lipid lowering

drugs: drugs: OTHEROTHER 0.820.82 0.61-1.100.61-1.10

Controlling for demographic, neurological and systemic risk factors

LIMITATIONSLIMITATIONS• Use of administrative data to identify study cohortsUse of administrative data to identify study cohorts

– Chart abstraction validation confirmed that new-onset Chart abstraction validation confirmed that new-onset epilepsy was accurately identified using our epilepsy was accurately identified using our algorithmalgorithm

– Diagnosis of obesity based on ICD 9 codesDiagnosis of obesity based on ICD 9 codes– Statin use based on pharmacy dataStatin use based on pharmacy data

• Healthy User Effect?Healthy User Effect?

• Did not use Medicare data for identifying comorbid Did not use Medicare data for identifying comorbid conditions.conditions.– May be underestimatesMay be underestimates

CONCLUSIONSCONCLUSIONS

• Consistent with previous research stroke Consistent with previous research stroke was the strongest risk factor for new-onset was the strongest risk factor for new-onset epilepsy in older patientsepilepsy in older patients

• Systemic risk factors were not associated Systemic risk factors were not associated with an with an independent independent riskrisk– Association of systemic risk factors may work indirectly Association of systemic risk factors may work indirectly

through increased risk for stroke and dementia in older through increased risk for stroke and dementia in older menmen

• Potential protective mechanism of statins Potential protective mechanism of statins may be due to reduced risk for stroke.may be due to reduced risk for stroke.

ImpactImpact

• 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.

Thank You!Thank You!

• Contact Information:

Mary Jo V. Pugh PhD, RN

pughm@uthscsa.edu

HSR&D, San Antonio