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

Background No comprehensive gonorrhea screening guidelines Median state-specific GC prevalence was 0.9% –During 2000, among women years seen in family planning settings (Poster 12) Most recent cost effectiveness study of GC screening – 1989 –Screening cost-effective if prevalence >2.0%

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

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.

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?

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)

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%

Proportion of GC positive tests among women by predictors of GC

How does having either symptoms or CT affect GC status?

Proportion of GC positive tests among women by symptom/CT status 0.5% 2.1% N=21,324N=7,266

Proportion of GC positive tests is 2.5 times higher in younger women. How does this vary by symptoms/CT status?

% of GC positive tests among women by symptom/CT status & age

African Americans have 5 times higher prevalence of GC than other race/ethnicities How does this vary by symptoms/CT status?

% of GC positive tests among women by symptom/CT status & race/ethnicity

The proportion of women with either symptoms or chlamydia among all women tested N=28,590

Given these low prevalences of GC, what are the consequences?

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)

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

PPV* of observed GC prevalence compared to observed CT prevalence in CA Family Planning Data: 2000 *Assuming 95% sensitivity & 99.5% specificity

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.

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.

Summary Con’t 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.

Recommendations If continue testing at current prevalence, confirmatory testing should be considered San Francisco –Discontinue screening in sites with a GC prevalence of <2%. –Perform diagnostic testing based on signs/symptoms and result of CT test on women <35 years. Cost effectiveness studies are needed

Fiscal Impact of GC testing on Family Pact: Fiscal Year ,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.