Evaluation of Gonorrhea Screening in Family Planning Settings: California 2000

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Evaluation of Gonorrhea Screening in Family
Planning Settings California 2000

• CK Kent, M Brammeier, G Bolan, N Casas,
• M Funabiku, P Blackburn
• Region IX Infertility Prevention Project

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Background

• No comprehensive gonorrhea screening guidelines
• Median state-specific GC prevalence was 0.9
• During 2000, among women 15-24 years seen in
  family planning settings (Poster 12)
• Most recent cost effectiveness study of GC
  screening 1989
• Screening cost-effective if prevalence gt2.0

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Objective

• To evaluate gonorrhea screening of women in
  family planning settings in order to better
  target screening.

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Data Sources

• Year 2000 data.
• 30 participating family planning clinics in
  California serving as sentinel screening sites.
• Examined gonorrhea (GC) chlamydia (CT) test
  results, symptoms (Sx), age, race/ethnicity.

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Questions to Consider

• Prevalence of GC?
• How well do symptoms predict GC?
• How well does having CT predict GC?
• How well does having either symptoms OR CT
  predict GC?
• Does this vary by age or race/ethnicity?

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Test Results

• 93 of women tested for CT were also tested for
  GC.
• CT positive tests 4.9 (1,497/30,568)
• GC positive tests 0.9 (257/28,590)

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How does GC prevalence vary by sites?

• Range of prevalence 0.0 - 2.5
• Two of 30 (6.9) sites had prevalence greater
  than 2

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Proportion of GC positive tests among women by
predictors of GC
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How does having either symptoms or CT affect GC
status?
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Proportion of GC positive tests among women by
symptom/CT status
2.1
0.5
N21,324
N7,266
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Proportion of GC positive tests is 2.5 times
higher in younger women. How does this vary
by symptoms/CT status?
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of GC positive tests among women by symptom/CT
status age
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African Americans have 5 times higher prevalence
of GC than other race/ethnicitiesHow does this
vary by symptoms/CT status?
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of GC positive tests among women by symptom/CT
status race/ethnicity
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The proportion of women with either symptoms or
chlamydia among all women tested
N28,590
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Given these low prevalences of GC, what are the
consequences?
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Positive Predictive Value (PPV) Observed
Prevalence by True Prevalence in Population
Assuming Tests with a Sensitivity of 95
Specificities of 99.0 or 99.5
(Note see poster 79 for more details)
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Potential Human Costsof False Positives

• Unnecessary treatment
• Lost time/expense for follow-up visit
• Damaged relationships
• Increased risk of domestic violence (particularly
  if partner is negative)

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PPV of observed GC prevalence compared to
observed CT prevalence in CA Family Planning
Data 2000
Assuming 95 sensitivity 99.5 specificity
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Potential Fiscal Impact of GC testing on
California Family Pact

• Assume 600,000 GC tests billed 50 were
  amplified tests.
• 19,800,000 reimbursed for GC testing.
• Costs will increase as more providers and
  laboratories switch to amplified testing.

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Summary

• Prevalence of GC among women screened in family
  planning settings in California very low (0.9).
• If tests being used for GC screening are 99.5
  specific, approximately 50 of test positives are
  false positives. Much higher false positive rate
  if tests are less specific.

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Summary Cont

• If perform only diagnostic GC testing among women
  with symptoms or CT, reduce testing by 75.
• Substantial resources are being devoted to GC
  screening in California that could potentially be
  used for other public health purposes.

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Recommendations

• If continue testing at current prevalence,
  confirmatory testing should be considered
• San Francisco
• Discontinue screening in sites with a GC
  prevalence of lt2.
• Perform diagnostic testing based on
  signs/symptoms and result of CT test on women lt35
  years.
• Cost effectiveness studies are needed

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Fiscal Impact of GC testing on Family Pact
Fiscal Year 1999-2000

• 613,000 GC tests billed (52 were amplified
  tests).
• 20,000,000 reimbursed for all GC testing.
• About 90 of women who are tested for CT are also
  tested for GC.
• 58 increase in laboratory costs due to switch to
  amplified testing for CT GC.