Bostons Surveillance System

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Bostons Surveillance System

• John Auerbach
• Executive Director
• Boston Public Health Commission

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Bostons Surveillance System An Evolving
Approach to Detecting Disease

• Historically strong doctor/nurse run
• communicable disease control unit
• Development of Citywide Volume-Based Surveillance
  System 2001
• Enhancement of Citywide Surveillance System to
  clinical and demographic information 2004

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Why Boston Prioritized a Strong Surveillance
System?

• Largest city in the State
• Multiple hospitals and health care facilities
  complicate timely gathering of information
• Strong local, state and federal support for
  health department activities
• Early and mounting fears of terrorist threats

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Volume Based Surveillance in Boston (1)

• A collaborative process began in January 2000
  with a federal grant
• Guided by a Surveillance Task Force composed of
  City and State health officials, hospital
  representatives, EMS and Poison control

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Volume Based Surveillance in Boston (2)

• Primary sources
• Emergency department and urgent care visits
• Secondary sources
• Poison Control Center
• Boston Emergency Services
• Death certificates

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Volume Based Surveillance in Boston (3)

• 12 acute care sites (10 hospital and 2 health
  center sites) electronically send data to BPHC
  every 24 hours via SFTP
• Site specific data automatically compared to site
  specific pre-set thresholds
• For sites over threshold a follow-up form is sent
  to a 24/7 on site contact to obtain additional
  information

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Volume Based Surveillance in Boston (4)

• Potential clusters or unusual cases identified
  on initial assessment are investigated by BPHC
  nurses using routine health department protocols
• Complete data are typically available within 12
  hours after the close of a 24 hour data period

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VOLUME BASED SURVEILLANCE DATA SOURCES
BOSTON EMS
Poison Control Center
BOSTON HOSPITALS/ HEALTH CENTERS


MDPH HEALTH ALERT NETWORK (HAN)
BPHC MORTALITY DATA (Death Certificates)
BPHC CDC
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Volume Based Surveillance Results

• System detected morbidity associated with a heat
  wave result prevention alerts
• Volume data corresponds well with influenza
  activity
• System detected norovirus activity (12/02)
• System identified changes in response to anthrax
  scare result hospital notices

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Added Benefits

• Planning process strengthened relationship
  between health department and hospitals
• Established regular communication between CDC
  nurses and ED personnel
• Created computer-based communication vehicle
  useful for transmitting advisories or responding
  to inquiries

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WWW.BPHC.ORG
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Volume Based Surveillance

• Easily re-created quickly if computer systems
  fail, BUT
• Non-specific for infectious diseases
• Relies on follow-up from the health care site to
  determine cause of volume exceedance
• Does not provide initial demographic or clinical
  information to begin detailed epidemiologic
  analysis

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2004 Democratic National Convention Provides
Opportunity to Enhance System

• 1st political convention since 9/11
• Prioritized perception of need among hospitals
  and government
• Reinforced appropriateness of use of emergency
  preparedness funding
• Conditions ripe for enhancement given existing
  surveillance system

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Development of Syndromic Surveillance in Boston

• In fall of 2003, convened existing partners in
  the volume based surveillance with following
  goals for enhancing system
• Gather clinical and demographic information
• Minimize additional effort on part of reporters
• Set timeline to have system operational by July,
  2004
• Coordinate with State and Federal health agencies
  using existing analytical programs

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Cooperation with the hospitals was strong but
just in caseBoston Board of Health passed a
Citywide regulation to require participation of
hospitals in system
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The Syndromic Surveillance Emerges

• Reporting sites 10 hospital EDs
• Automated daily electronic transfer using SFTP of
  prior 24 hour line-by-line patient data
• Age, gender, and race/ethnicity
• Zip code of primary residence
• Chief complaint
• ICD-9 for ED visit (within days)
• Unique patient identifier (HIPAA-compliant)

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Syndromic Surveillance Boston

• Chief complaint data categorized into syndromes
  using CoCo
• Data analyzed using CUSUM (EARS, CDC)
• Aberrations flagged for additional follow-up
• Findings reviewed by public health nurse or
  epidemiologist

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Syndromic Surveillance Follow-up (1)

• Follow-up is a critical component of the system
• If cluster or unusual case noted, secondary data
  sources reviewed
• Line-by-line Poison Control Center data
• Line-by-line Boston EMS data
• Death certificates
• ED faxes records of interest to BPHC on request

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Syndromic Surveillance Follow-up (2)

• Information gathered from community based sources
  as indicated
• Normally day care centers, schools and chronic
  care facilities
• During DNC surveillance also will occur at key
  hotels, the Fleet Center and protest grounds
• Findings reported to community to enhance
  additional case finding

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Advantages of Syndromic Surveillance

• More detailed initial data provided allowing for
  targeted follow-up activities
• Availability of zip code can help to locate a
  cluster in space
• Expanded initial data provided to BPHC reduces
  the burden on participating sites with regard to
  providing follow-up based on volume number

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Syndromic Surveillance Challenges

• Validity of chief complaint data Do different
  populations describe the same illness
  differently?
• Computer systems go down complex data are
  difficult to retrieve manually
• These systems only provide an initial clue, not
  the final answer.

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Surveillance Lessons Learned (1)

• To be sustainable long term, systems must be
  electronic and automatic to the extent possible
• Add on systems are not likely to be sustainable
• Computer systems go down (sometimes for days)
• Back-up plans are critical
• Complex data is difficult to retrieve manually
• Creative problem solving is essential especially
  on weekends and holidays

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Surveillance Lessons Learned (2)

• Follow-up is the most important part of any
  system
• Syndromic surveillance only provides an initial
  signal to be explored
• Integrate follow-up into health department
  routine
• Communication is key
• Feedback to providers is critical
• Dont abandon case reporting (but make it as
  automated as possible)

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Final Thoughts

• More attention needs to be paid to what happens
  when the buzzer goes off
• The goal of these systems is early detection of a
  public health problem so that appropriate control
  measures can be introduced
• But the capacity to respond is key

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Questions?