Case Studies in the Use of the National Poison Data System NPDS

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Case Studies in the Use of the National Poison
Data System (NPDS)

• Colleen A. Martin, MSPH
• Amy Wolkin, MSPH
• Centers for Disease Control and Prevention (CDC)
• Alvin C. Bronstein, MD
• American Association of Poison Control Centers
  (AAPCC)

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What is NPDS?

• Web-based application for the analysis,
  visualization, and reporting of near real-time
  data from 61 regional Poison Centers (PCs)
• Operated by the American Association of Poison
  Control Centers (AAPCC)
• Collaboration with National Center for
  Environmental Health (NCEH)
• System users include
• AAPCC and CDC
• Individual regional PCs
• State Health Departments

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NPDS Surveillance Goals

• Improve public health surveillance for chemical
  and toxin exposures and associated illness
• Identify potential chemical exposure events to
  enable a rapid and appropriate public health
  response
• Find potential cases and provide situational
  awareness during an event

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Poison Centers (PCs)

• 61 PCs in the US

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Poison Centers

• National toll-free number
• Calls from the public (85) and health
• care professionals (15)
• PC staff includes medical toxicologists,
  pharmacists, and specialists in poison
  information (SPIs)
• Callers usually seeking diagnostic or treatment
  recommendations

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Call Data

• More than 4.2 million calls in 2007
• Exposure Calls
• Concern about exposure to a substance
• 60 (2.6 million) calls
• Information calls
• No exposure
• 40 (1.6 million) calls

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Data Collection

• Primary responsibility of SPIs is clinical case
  management
• Data entered into regional PC server as caller
  provides it
• Demographic data and clinical data
• 131 pre-coded clinical effects (signs and
  symptoms)
• 72 pre-coded treatment, decontamination and
  management options
• PCs upload data to NPDS on average every 11
  minutes

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NPDS Data Flow
Health Professionals Hospitals
General Public
Local Poison Center
NPDS

• Data elements include
• Time
• Date
• Call type
• Exposure duration

• Cause of exposure
• Symptoms
• Severity
• Treatment

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Surveillance Methods

• Call Volume
• Number of hourly calls
• Threshold historical baseline avg 3 SD
• Clinical effects (signs and symptoms)
• Number of clinical effects during 24 hr period
• Threshold historical baseline avg 2 SD
• Case-based definitions
• Collection of clinical effects for specific agent
  or occurrence specific chemicals, toxins, or
  products
• Each call is flagged as a case

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Examples of Case-Based Definitions
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Anomaly Characterization

• NPDS generates automated anomaly emails
• Data reviewed by AAPCC surveillance team and NCEH
• Cluster characterization
• Number of reports
• Geographic dispersion
• Magnitude above the threshold
• Illness severity
• Evidence of a shared exposure
• Individual cases
• Lab data
• Information from clinical care providers, public
  health officials
• Regional PCs contacted as required
• Confirmed public health issues communicated to
  state public health and NCEH

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Use of NPDS for Outbreak Response

• Conduct national surveillance
• Identify new potential cases
• Track temporal and spatial distribution
• Monitor illness severity

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Case Study Cluster Detection

• Retrospective analysis of clusters identified
  2/15/08 to 6/15/08
• Cluster statistically significant increase in
  callers reported clinical effects
• Detection algorithm settings for time and space
• Previous 24 hours
• National data
• Public health significance classified by AAPCC
  surveillance team at time of the anomaly as yes,
  no, or unknown

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Case Study Cluster Detection

• Median anomalies per day 2 (range 0 to 7)
• Anomalies on 83 of 122 days (68)
• 78 (94) not of public health significance
• 2 (2.4) were of unknown significance
• Clinical effects miscoded
• Reclassified as having no significance
• 15 adults treated in ED for chest pain due to
  acute exposure to a pool algicide
• Reclassified as having PH significance

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Case Study Cluster Detection

• 3 (3.6) had public health significance
• 38 school children with nausea, rash, and dyspnea
  after exposure to cologne
• 36 students and one adult went to the ED due to
  chlorine gas exposure
• 65 calls regarding exposure to tomatoes
  potentially contaminated with salmonella during
  nationwide outbreak

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Case Study Outbreak of Selenosis

• FDA press release March 27, 2008

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Case Study Outbreak of Selenosis

• March 2008, FDA began receiving reports of
  clusters of illness associated with a dietary
  supplement product
• Total Body Formula
• Symptoms hair loss, GI problems, joint pain,
  nausea
• FDA contacted NCEH to determine if NPDS was
  identifying related reports from PCs

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Case Study Outbreak of Selenosis

• NCEH set up ad hoc case definition
• Human AND exposure AND dietary supplement AND
  (nausea OR diarrhea OR pain OR muscle weakness OR
  neuropathy)
• Could not include hair loss in definition since
  it was not one of the 131 coded clinical effects
  
• Needed to develop a product code to better
  identify exposed persons

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Case Study Outbreak of Selenosis

• AAPCC developed temporary product code
• Sent product alert to all regional PCs
• NCEH created new case-based definition based on
  product code

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Case Study Outbreak of Selenosis

• Revised definition Human exposure Code 22
• Implemented new code March 25, 2008

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Case Study Outbreak of Selenosis

• PCs provided treatment and case management
  guidelines
• NPDS used to track temporal and geographic
  distribution
• 3/11/08 to 6/4/08 170 human exposures in 8
  states
• 136 (80) reported clinical effects
• Generalized pain (25.3)
• Diarrhea (24.1)
• Nausea (12.4).
• PCs reported potential cases to state HDs
• Use of NPDS increased collaboration between state
  HDs, PCs, FDA, and CDC.

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NPDS Tasks In Progress

• Develop a community of practice to encourage
  collaboration between state HDs and PCs
• Refine protocols for anomaly characterization and
  information sharing
• Implement system enhancements to improve
  analysis, visualization, and reporting
  functionality
• Exchange information with other CDC national
  biosurveillance programs during events

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Conclusions

• NPDS provides near real-time capability for
  identifying clusters and potential cases during
  an outbreak
• AAPCC surveillance team provides a link between
  NCEH and the regional PCs
• Selenium exposure event allowed for system
  testing and augmenting relationships between CDC,
  FDA, state HDs, and PCs

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Further Information

• AAPCC Annual Report available at
  http//www.aapcc.org/Annual20Reports/06Report/200
  620Annual20Report20Final.pdf
• Wolkin AF, et al. Early detection of illness
  associated with poisonings of public health
  significance. Annals of Emergency Medicine.
  200647(2)170-6.

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Acknowledgements

• CDC
• Colleen Martin
• Cristina Cooper
• Helen Schurz Rogers
• Josh Schier
• Adrianne Holmes
• Lauren Lewis

• AAPCC
• James Hirt
• Stuart Heard
• Alvin Bronstein
• Sandy Giffin
• Douglas Borys
• Blaine Benson
• Richard Thomas

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Thank you!

• Amy Wolkin
• AJF(_at_CDC.GOV
• 770-488-3402

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NPDS Application

• Investigate anomalies
• Create definitions
• View Reports

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Example of National Clinical Effects Anomaly
Email
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Figure 1
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Clinical Effects by System
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Investigating Anomalies
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Inside NPDS
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Anomaly Monitor
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Anomaly Analysis Complete Email
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NPDS Application

• Investigate anomalies/alerts
• Create case-based definitions
• Run reports

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Case-Based Definitions
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NPDS Application

• Investigate anomalies/alerts
• Create case-based definitions
• Run Reports

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Enterprise Reports