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 SitesNEISS Sites

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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

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AcknowledgementsAcknowledgements

• CPSC– Terri Nelson– Cathleen Irish

• FDA– Judy Staffa, PhD, RPh– Gerald Dal Pan, MD, MHS– Anne Trontell, MD, MPH

• CDC– Dan Budnitz, MD, MPH– Kelly Weidenbach, MPH– Lee Annest, PhD

• Participating NEISS Hospitals– Data Coordinators– Emergency Dept. Staff