Los Angeles County STD Surveillance Data Surveillance, Sources, Methods and Issues

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Los Angeles County STD SurveillanceData
Surveillance, Sources, Methods and Issues

• Lisa V. Smith, MS, DrPH
• Director, Epidemiology Unit
• Los Angeles County Sexually Transmitted Disease
  Program

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Overview

• What are active and passive surveillance?
• Which STDs are reportable?
• What is the impact of LA County morbidity on
  state and national STD surveillance?
• How are cases reported to LA County (LAC), State,
  and CDC?
• What are rates and how are they used?
• What are the limitations and benefits of LAC STD
  surveillance data?

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What is Surveillance?

• Systematic collection and evaluation of
• Morbidity and mortality data
• Special reports of field investigation of
  epidemics and individual cases
• Data on the isolation and identification of
  infectious agents by public or private
  laboratories
• Information regarding immunity levels in certain
  populations

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What do we do with this information?

• Estimate the magnitude of health conditions
• in at-risk populations
• Detect sudden changes in occurrence and
  distribution
• Detect changes in drug resistance
• Identify changes in health care practices
• Evaluate control strategies
• Allocate resources

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Data Sources

• Active Surveillance
  Conditions of particular importance (outbreaks
  and epidemics)
• Passive Surveillance
  Routine notifiable disease surveillance reported
  case by case

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Active Surveillance

• Casefinding
• Prevalence Monitoring
• Sentinel Surveillance K-11, Juvenile Hall,
  Family Planning Clinics, Bathhouses, Syphilis
  Elimination Project (MSM)
• Mass Screening Mobile testing, Adult Movie
  Industry
• Epidemiologic research Primary HIV infection

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Passive Surveillance

• Accounts for most of the reported cases
• Relatively simple compared to active surveillance
• Limited by variability and incompleteness
• May fail to identify outbreaks
• Usually augmented by active surveillance

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Which STDs are reportable?

• Health Care Provider
• Syphilis
• Gonorrhea
• Chlamydia
• Chancroid
• PID
• NGU

• Clinical Laboratory
• Syphilis (Treponema pallidum)
• Gonorrhea (Neisseria gonorrhoeae)
• Chlamydia (Chlamydia trachomatis)

California Code of Regulations, Title 17, Public
Health, Section 2500, 1996 Report by FAX,
telephone, or mail w/in one working day of
identification Report by FAX, telephone, or mail
w/in seven working days of identification
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Reported Sexually Transmitted Diseases United
States, 2003
AIDS 43,158 (3.6)
Source CDC Sexually Transmitted Disease Report,
2001
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Reported Sexually Transmitted DiseasesLos
Angeles County, 2003
Provisional data due to reporting delays Source
LAC DHS STD/ACD Programs Provisional Data, 2003
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What is the Impact of LAC Morbidity on STD
Reportingin CA US

• 36,555 Chlamydia (31 CA 4 US)
• 8,008 Gonorrhea (31 CA 2 US)
• 442 PS Syphilis (34 CA 6 US)
• 365 Early Latent (54 CA 4 US)
• 28 Congenital Syphilis (47 CA 7 US)

LA, CA, CDC STD Surveillance, 2003 PSchancres/l
esions (90 days-6 months) EL asymptomatic (w/in
12 months)
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How are cases reported to the STD Program?

• Health providers use forms to report STD cases to
  the health department
• STDP uses a dual reporting system to gather
  information on STD morbidity
• Confidential Morbidity Forms (CMRs)
• Submitted by health providers
• Laboratory Report Forms
• Submitted by laboratory facilities

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Medical Providers STD Reporting Form
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Medical Providers STD Reporting Form
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Example of Laboratory STD Reporting Form for CT/GC
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STD Surveillance Process

• Case Definition Differential clinical diagnosis
  of reportable STDs to distinguish between cases
  and noncases
• Population Definition Identify area of interest
  to determine residency and population denominators

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STD Surveillance
All CA county reports
Public Health Action
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85.2 LA (2003) 73.9 CA (2003) 116.2 US (2003)
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Why do we use rates and not absolute numbers?

• Total number of reported cases appears to be
  adequate, but are these numbers comparable?

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Absolute Numbers(Males Only)
Black Hispanic Asian White
Reported Chlamydia Cases in 2001 1,965 2,720 181 622
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STD Rates
multiplier

• Number of new events in specific period
• Average population during specific period

X 10n

Essential for comparing dx in different
populations Pop A 1,000/10,000 100 cases
per 1000 population Pop B 1,000/1,000,000 1
case per 1000 population
Assumes average population and population at
risk are comparable.
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Population Rates(Males Only)
Black Hispanic Asian White
Reported ChlamydiaCases in 2001 1,965 2,720 181 622
Population Estimates 396,614 2,297,208 593,633 1,590,586
Rate per 100,000 Population 495 118 30 39
2000 Estimates
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How are these rates used?
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1. Identify overall trends
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Chlamydia Rates by Gender
2. Describe disease patterns
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3. Describe spatial distributions
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4. Target interventions
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Additional Resources National Center for Health
Statistics

• Nations principal health statistics agency
• Data are used to guide actions and policies, as
  well as
• Document health status of populations and
  important subgroups
• Identify disparities in health status by
  race/ethnicity, socio-economic status, region,
  etc.
• Monitor trends in health status and health care
  delivery
• Support biomedical and health research
• Evaluate the impact of health care

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National Surveillance Reports(www.cdc.gov/nchs)

• National Health and Nutrition Examination Survey
  (NHANES)
• Contains important information on sexual
  behaviors
• National Health Interview Survey (NHIS)
• AIDS Knowledge and Attitudes Supplement
• Young Risk Behavior Surveillance System (YRBSS)
  (www.cdc.gov/yrbss)
• Survey monitors sexual behaviors that contribute
  to unwanted pregnancies and STD/HIV
• UCLA ISSR website http//www.sscnet.ucla.edu/issr
  /da/catalog.htm

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Data Limitations

• Incomplete case reporting
• Reporting delays
• Missing information
• Underreporting (asymptomatic cases)
• Reporting bias
• Stigmatized condition
• Public vs. Private

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How Can We Improve Data Quality?

• Improve data retrieval system
• Phone Shop
• Increase provider awareness of reporting
  regulations
• In-services
• Mass Mailings
• In person visits
• Implement CDC NEDSS web-based surveillance

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What are the Benefits of STD Surveillance?

• Though flawed, STD surveillance data provides
• the best estimate of magnitude of disease in
  at-risk populations
• Numbers are the tip of the iceberg
• the basis for epidemiologic research
• a system to monitor compliance with CDC treatment
  guidelines

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Key Points to Ponder

• To date, six STDs are reportable in California
• Chlamydia is the most frequently reported STD in
  the United States
• Los Angeles accounts for 1 of 3 STD cases in
  California and 1 of 25 cases in the United States
• Most of the STD data come from passive
  surveillance systems and dual reporting
• Data limitations include incomplete case
  reporting and reporting bias
• Nevertheless, STD surveillance data provides the
  best estimate of magnitude of disease in
  at-risk populations

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Resources

• Los Angeles County
  http//lapublichealth.org/std/
• California http//www.dhs.ca.gov/ps/dcdc/pdf/c
  dtables/febcm03.pdf
• Centers for Disease Control and Prevention
  http//www.cdc.gov/
• http//www.cdc.gov/nedss/

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