The National Electronic Injury The National Electronic Injury Surveillance System: Cooperative Surveillance System: Cooperative Adverse Drug Events Surveillance Adverse Drug Events Surveillance
System (NEISS-CADES)System (NEISS-CADES)
Aaron B. Mendelsohn, PhD, MPHOffice of Drug Safety
Food & Drug Administration18 May 2005
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History of NEISS-CADESHistory of NEISS-CADES
• 1971: Consumer Product Safety Commission implemented National Electronic Injury Surveillance System (NEISS) to detect injuries associated with consumer products
• 2000: NEISS expanded to collect data on all injuries (e.g., violence, occupational, adverse drug events)
• 2002: NEISS-CADES created through FDA, CDC, and CPSC collaboration to collect specific details (e.g., route of administration) for ADEs
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NEISS-CADES participating sitesNEISS-CADES participating sites
• Ongoing survey of 64 US health care facilities
• Stratified probability sample of US hospitals with 24-hour ED and minimum of 6 beds– Selection based upon geographic region, size,
and pediatric/adult status– National projections obtainable
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NEISS-CADES drug definitionNEISS-CADES drug definition
• Prescription medications• Over-the-counter medications• Topical medications • Vaccinations, immunizations • Vitamins, dietary supplements, and herbals
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Adverse drug event (ADE) definitionAdverse drug event (ADE) definition• NEISS-CADES defines an ADE as an injury related to
the outpatient use of a drug and resulting from:– Allergic reaction– Side effect– Unintentional overdose– Secondary effect
• Exclusions: – Intentional drug injuries, e.g., suicide attempts– Injuries resulting from alcohol, tobacco, and illicit
drugs
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Data collected in NEISS-CADESData collected in NEISS-CADES
• Patient demographics• Drug data
– Name of medication– Dose, frequency, duration, route– Concomitant medications
• Patient diagnosis(es)• Tests performed and treatments received in ED • Patient disposition• Brief narrative description of event
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NEISS-CADES data flowNEISS-CADES data flow
ADE documented in patient chart
NEISS coder abstracts data
Patient visits ED
Analysis Database
CPSC removes personal identifiers & quality checks
CDC reviews raw data &
directs quality control
FDA contracts medical coding
FDA, CDC collaborate on data analyses
Disseminate findings &
prevent ADEs
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Preliminary findings from NEISS-Preliminary findings from NEISS-CADES: Pilot study resultsCADES: Pilot study results
• Conducted by multi-agency / multi-disciplinary team
• Analysis of data from 9 NEISS-CADES sites– Stratified (hospital size), convenience sample
• Time period: July 2002 – September 2002
• Published in Annals of Emergency Medicine, 2005
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Characteristics of patients experiencing Characteristics of patients experiencing ADEs (N=598): NEISS-CADES pilot studyADEs (N=598): NEISS-CADES pilot study
Patient Characteristic n (%)
Age (years)
Median (range)
25th and 75th percentile
41 (0 – 101)
18, 62
Female sex 382 (63.9)
Disposition
Treated & released
Hospitalized
Left against med advice
Died (in ED)
541 (90.5)
52 (8.7)
5 (0.8)
0 (0)
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Most common drug classes associated Most common drug classes associated with ADEs: NEISS-CADES pilot studywith ADEs: NEISS-CADES pilot study
Drug Class
ADEs
(N=598) %
Hospitalized
(N=52) %
Antimicrobials 96 16.1 0 0
Diabetic agents 78 13.0 9 17.3
Cardiovascular 51 8.5 12 23.1
Non-opioid analgesics
49 8.2 1 1.9
Psychiatric 42 7.0 4 7.7
Opioids 39 6.5 2 3.8
Anticoagulants 28 4.7 8 15.4
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Mechanisms of injury* associated with Mechanisms of injury* associated with ADEs: NEISS-CADES pilot studyADEs: NEISS-CADES pilot study
Mechanism ADEs
(N=598) %
Hospitalized
(N=52) %
Unintentional overdose
233 43.6 38 73.1
Side effect 185 30.9 8 15.4
Allergic reaction 155 25.9 4 7.7
Secondary effect
25 4.2 2 3.8
*Based upon classifications in BMJ 1998, 316:1511-1514.
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NEISS-CADES adverse drug NEISS-CADES adverse drug event examplesevent examples
• 68-year old male with gastrointestinal bleeding following warfarin use, held for observation (unintentional overdose)
• 54-year old female became hypoglycemic following overdose of insulin, treated and released (unintentional overdose)
• 7-year old female with rash following antibiotic A, treated and released (allergic reaction)
• 2-year old male with tremors following albuterol, treated and released (side effect)
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Current research activities with Current research activities with NEISS-CADES dataNEISS-CADES data
• Analysis of first 12 months of data collection– National estimates– Most important drugs and drug classes– Most common mechanisms of injury– Factors leading to hospitalization
• Examine ADEs in understudied patient subgroups – e.g., elderly, pediatric patients
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NEISS-CADES limitationsNEISS-CADES limitations
• System only captures certain ADEs– Acute events– Outpatient setting– Presented to EDs– Recognized by attending physician
• Relies on quality and completeness of ED charts
• Training of coders
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NEISS-CADES strengthsNEISS-CADES strengths
• Nationally representative, active surveillance system for detecting ADEs in outpatient setting – Possible to estimate the magnitude of drug safety
concern
• Capable of capturing ADEs related to older drugs and those recently released to market
• Stability
• Adaptability
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NEISS-CADES strengths (continued)NEISS-CADES strengths (continued)
• Detailed data collection
• Timeliness– ~70% of events within 7 days
• Successful, cost-efficient collaboration between multiple federal agencies