Giardiasis Diagnosis and Treatment in the United States: New Tools - - PowerPoint PPT Presentation

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Giardiasis Diagnosis and Treatment in the United States: New Tools - - PowerPoint PPT Presentation

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Giardiasis Diagnosis and Treatment in the United States: New Tools for an Old Disease Karlyn Beer, MS, PhD Epidemic Intelligence Service Fellow Division of Foodborne, Waterborne and Environmental Diseases CDC May 26, 2016 2016 HCIL Symposium

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Giardiasis Diagnosis and Treatment in the United States: New Tools for an Old Disease

Karlyn Beer, MS, PhD

Epidemic Intelligence Service Fellow Division of Foodborne, Waterborne and Environmental Diseases CDC May 26, 2016 2016 HCIL Symposium

National Center for Emerging and Zoonotic Infectious Diseases Division of Foodborne, Waterborne and Environmental Diseases

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Giardiasis in the United States

  • Giardia intestinalis parasite
  • 1.2 million cases/year
  • Hospitalizations cost $34

million/year

  • 8% of US cases are travel-

associated

  • Children 1–9 years: Highest

annual incidence

Giardia intestinalis

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Giardia transmission in the United States

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Highlights from Giardia’s long history

1632

Van Leeuwenhoek’s Microscope

1965 2002 1992

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Prolonged GI symptoms Giardia diagnostic test Giardiasis diagnosis (Dx) Antiparasitic prescription (Rx)

Giardiasis symptoms, diagnosis and treatment: an expected sequence

Antibiotic Rx

  • Prolonged, non-bloody

diarrhea

  • Abdominal cramps
  • Bloating
  • Flatulence
  • Long-term sequelae

Adapted from Gardner, 2001. Clin Microbiol Rev. Figure 2

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Prolonged GI symptoms Giardia diagnostic test Giardiasis diagnosis (Dx) Antiparasitic prescription (Rx)

Recommendations vs. reality

Antibiotic Rx

  • Is this sequence actually

happening in the US?

  • If not, how do patents get

diagnosed and treated?

  • Do pediatric and adult

giardiasis care differ?

Adapted from Gardner, 2001. Clin Microbiol Rev. Figure 2

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Giardiasis is difficult to diagnose

  • Nonspecific symptoms and low clinical suspicion
  • Parasites are shed intermittently in feces
  • Multiple specimens recommended
  • Providers must order Giardia-specific tests

…which can lead to problems

  • Delayed diagnoses
  • Disrupted daily life
  • Ineffective antibiotic prescriptions  antimicrobial resistance

Cantey, 2011. Am J Med; Attias, 2015. Pediat Theraput

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SLIDE 8
  • Actual vs. expected patient care is

unknown

  • Reason to suspect room for

improvement

We can’t fix what we don’t measure

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Study aims

  • 1. Describe pediatric and adult giardiasis clinical

care in the US

  • GI symptom visits
  • Diagnostic tests
  • Antiparasitic prescriptions
  • Antibiotic prescriptions
  • 2. Quantify and characterize the use of the expected

giardiasis care sequence

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MarketScan insurance claims database

  • Large (enormous) database of health insurance claims data
  • ~170 million unique persons
  • 1995–present
  • Claims records for:
  • Hospital stays
  • Outpatient office visits
  • Diagnostic procedures
  • Prescriptions
  • Commercially insured, excluding Medicare/Medicaid
  • Longitudinal data
  • Patient = event timeline
  • Big data, more economical than a cohort study
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Example of one person’s insurance claims data in MarketScan

Date of Service Procedure Code Diagnosis Code Rx Name Copay

5/7/15 Office visit Diarrhea $64.78 5/14/15 Office visit Giardia $50.39 5/14/15 Ova and Parasite - stool Giardia $30.29 5/14/15 METRONIDAZOLE $15.00 6/9/15 Giardia Rapid Test Giardia $36.48

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N = 2,995

  • ≥1 giardiasis outpatient visit: ICD-9-CM code

007.1

  • Diagnosed from 2006–2010
  • Evidence of Rx coverage
  • Enrolled 90 days before and after diagnosis

MarketScan giardiasis cohort

  • 90 days

+90 days

Giardiasis Dx

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Characteristic N % Female gender 1,499 50.0 Age (years) 0–17 915 30.6 18–44 1,151 38.4 45-64 929 31.0 US Census Region of residence South 1,297 43.3 West 774 25.8 Midwest 544 18.2 Northeast 361 12.1 Unknown 19 0.6

MarketScan giardiasis cohort characteristics (N=2,995)

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Giardiasis outpatients as event timelines in MarketScan

Antiparasitic Rx GI symptom Giardia test

Giardiasis Dx

  • 90 days

+90 days

Antibiotic Rx

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Event-specific descriptive results

  • 48% were diagnosed on their first symptom visit
  • 50% had no Giardia diagnostic tests
  • 64% had ≥1 antiparasitic prescription
  • 27% had ≥1 antibiotic prescription
  • Children had more tests and fewer prescriptions

than adults

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The whole tub of ice cream

First Dx Giardiasis outpatients (N=2,995)

  • 90 days

+90 days

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A new tool for finding patterns in longitudinal data

EventFlow: Visual Analysis of Temporal Event Sequences and Advanced Strategies for Healthcare Discovery

http://www.cs.umd.edu/hcil/eventflow/

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EventFlow: simplifying complex longitudinal data

Scatterplot Example EventFlow Output

http://www.cs.umd.edu/hcil/eventflow/

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Persistent GI symptoms Giardia diagnostic test Giardiasis Dx Antiparasitic Rx

Expected giardiasis clinical event sequence

Antibiotic Rx

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Expected sequence query in EventFlow

Giardia diagnostic test Antiparasitic Rx Antibiotic Rx Antibiotic Rx

Sequential OR Concurrent

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Expected giardiasis clinical event sequence

  • 18% of outpatients followed the

expected sequence

  • No difference between children and

adults

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Time from outpatient’s first event

0 days

18% had the expected sequence (N=541)

http://www.cs.umd.edu/hcil/eventflow/

Outpatients with expected sequence

90 days

Antiparasitic Giardia test

# of patients per group Time between two events

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Time from outpatient’s first event

0 days

http://www.cs.umd.edu/hcil/eventflow/

Outpatients with expected sequence

90 days

96%: First event = Giardia test

Antiparasitic Giardia test

18% had the expected sequence (N=541)

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SLIDE 24

Time from outpatient’s first event

0 days

http://www.cs.umd.edu/hcil/eventflow/

Outpatients with expected sequence

90 days

96%: First event = Giardia test

Antiparasitic Giardia test

4%: Drug  Test  Drug … 18% had the expected sequence (N=541)

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Time from outpatient’s first event

0 days

Outpatients with expected sequence

90 days

86%: Test  Drug

Antiparasitic Giardia test

Median time: 4 days

http://www.cs.umd.edu/hcil/eventflow/

18% had the expected sequence (N=541)

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82% had unexpected sequences

  • Identify gaps between recommendation

and reality

  • How does care differ between children and

adults?

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0 days 60 days

Time from outpatient’s first event

Pediatric unexpected care sequences (n=807)

Children with unexpected sequence

http://www.cs.umd.edu/hcil/eventflow/

Antiparasitic Giardia test Antibiotic

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SLIDE 28

0 days

Time from outpatient’s first event

Pediatric unexpected care sequences (n=807)

Children with unexpected sequence

http://www.cs.umd.edu/hcil/eventflow/

Antiparasitic Giardia test Antibiotic

12%: First event = Antibiotic 39%: First event = Giardia test

60 days

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0 days

Time from outpatient’s first event

Pediatric unexpected care sequences (n=807)

Children with unexpected sequence

http://www.cs.umd.edu/hcil/eventflow/

60 days

Median time: 21 days

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0 days

Time from outpatient’s first event

Adult unexpected care sequences (n=1647)

Adults with unexpected sequence (n=1647)

http://www.cs.umd.edu/hcil/eventflow/

Antiparasitic Giardia test Antibiotic

27%: Antiparasitic only

60 days

45%: First event = Antiparasitic

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Unexpected care sequences compared

Number of outpatients

0 days

Time from first event

60 days 0 days 60 days

Age <18 years (n=807) Age 18–64 years (n=1647)

Antiparasitic Giardia test Antibiotic

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EventFlow analysis unlocked novel insights

  • Most outpatients do not have the expected care

sequence

  • Giardiasis care differs fundamentally by age
  • Children: Comprehensive testing workup
  • Adults: “Treat first, test later (or not)”
  • Findings will drive provider follow-up as we

develop revised guidance

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Interpret with care

  • Must analyze and validate patterns identified

with EventFlow

  • MarketScan: administrative data not collected for
  • ur study purpose expressly
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EventFlow

Public health research impact

  • Largest analysis of US

giardiasis diagnosis and treatment

  • First use of EventFlow

at CDC

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Future directions

  • Clinical guidance should incorporate insights from

cohort studies of patient care patterns

  • Recommend data visualization tools to

complement conventional analyses

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Acknowledgements

Coauthors

Sarah Collier Julia Gargano Epidemic Intelligence Service Program Jennifer Cope Katie Fullerton Jonathan Yoder Michael Beach Michele Hlavsa Virginia Roberts Elizabeth Adam Joana Yu Taryn Mecher Katie Smith Jacqui Hurd Hannah Reses Kathy Benedict

WDPB Domestic Team U of Maryland HCIL

Fan Du Catherine Plaisant Ben Shneiderman

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KBeer@cdc.gov

1600 Clifton Road NE, Atlanta, GA 30333 Telephone: 1-800-CDC-INFO (232-4636)/TTY: 1-888-232-6348 Visit: www.cdc.gov | Contact CDC at: 1-800-CDC-INFO or www.cdc.gov/info The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

National Center for Emerging and Zoonotic Infectious Diseases

Thank you

Division of Foodborne, Waterborne and Environmental Diseases