Repeat Chlamydial Infections in Region III Family Planning Clinics: Implications for Screening Programs Pamela G. Nathanson, Family Planning Council, Inc. Mary Dupuis Sammel, ScD and Michelle Berlin, MD, MPH Center for Clinical Epidemiology and Biostatistics University of Pennsylvania Medical Center Philadelphia, PA

Background The Region III Chlamydia Project has provided chlamydia screening and treatment for women as part of CDC’s National Infertility Prevention Program (IPP) since The Region III Chlamydia Project has provided chlamydia screening and treatment for women as part of CDC’s National Infertility Prevention Program (IPP) since All women under age 30 who undergo a pelvic exam are routinely screened for chlamydia in family planning (FP) clinics. All women under age 30 who undergo a pelvic exam are routinely screened for chlamydia in family planning (FP) clinics. Approximately 300,000 women are screened annually throughout the 8 project areas (Baltimore, Delaware, Maryland, Pennsylvania, Philadelphia, Virginia, West Virginia, Washington DC). Approximately 300,000 women are screened annually throughout the 8 project areas (Baltimore, Delaware, Maryland, Pennsylvania, Philadelphia, Virginia, West Virginia, Washington DC).

Screening Program Issues Anecdotal reports from providers suggested high levels of repeat chlamydia infections among women attending family planning clinics. Anecdotal reports from providers suggested high levels of repeat chlamydia infections among women attending family planning clinics. Increased efforts around partner management were initiated, with little concrete data on repeat infection rates. Increased efforts around partner management were initiated, with little concrete data on repeat infection rates. Some providers wanted to avoid repeat screenings of women testing negative on prior visits, but had no data to support this change in screening practices. Some providers wanted to avoid repeat screenings of women testing negative on prior visits, but had no data to support this change in screening practices.

Objectives To determine rates of repeat infections among women screened for chlamydia in family planning clinics in Region III between 1996 and To determine rates of repeat infections among women screened for chlamydia in family planning clinics in Region III between 1996 and To determine if a low-risk group could be identified that might not require repeat screening over time. To determine if a low-risk group could be identified that might not require repeat screening over time.

Methods Analysis was conducted on 174,278 tests performed on 73,107 women from 1996 to 1998 in 6 of 8 project areas (Baltimore, Delaware, Pennsylvania, Philadelphia, Virginia, Washington DC). Analysis was conducted on 174,278 tests performed on 73,107 women from 1996 to 1998 in 6 of 8 project areas (Baltimore, Delaware, Pennsylvania, Philadelphia, Virginia, Washington DC).

Description of Data 990,847 Number of records between ,139 Excluded records from males -161,327 Excluded records from non-family planning clinics -247,698 Excluded records from 2 areas without unique Ids ,683 Records from women with at least 1 visit -354,889 Excluded records with only 1 visit ,794 Records for 85,175 women with multiple visits -22,516 Records with discrepancies (mismatched age, etc.) ,278 Total records for 73,107 women

Methods Positivity rates for women with prior positive chlamydia tests were compared to those for women with prior negative tests. Positivity rates for women with prior positive chlamydia tests were compared to those for women with prior negative tests. Variables in the analysis included: Variables in the analysis included:  age  time since prior visit  project area where patient was tested.

Number of Visits Per Woman # of Visits Frequency% 253, , , , < <0.1 TOTAL73,

Demographic DistributionTOTAL73, % PROJECT AREA NPercent BaltimoreDelawareMarylandPennsylvaniaPhiladelphiaVirginia Washington DC West Virginia 2,0486,218031,92021,58910, %8.5%0.0%43.7%29.5%14.3%1.2%0.0% AGE (years) NPercent ,34623,93922,98214,48710,1231.8%32.8%31.5%19.9%13.9%

Infection Rates by Infection Status at Prior Visit Infected at Prior Visit Uninfected at Prior Visit Rate Ratio OVERALL19.7%3.7%5.4 Baltimore n=2, %3.5%5.9 Delaware n=6, %3.6%3.7 Pennsylvania n=31, %1.8%7.2 Philadelphia n=21, %6.1%4.2 Virginia n=10, %4.1%3.8 Wash DC n= %2.7%3.4

Infection Rates by Infection Status at Prior Visit –By Age Group Infected at Prior Visit Uninfected at Prior Visit RateRatio OVERALL19.7%3.7% – 14 yrs n=1, %8.7% – 19 yrs n=23, %6.0% – 24 yrs n=22, %3.9% – 29 yrs n=14, %2.3% yrs n=10, %1.1%10.8

Infection Rates by Infection Status at Prior Visit and Time Since Prior Visit Infected at Prior Visit Uninfected at Prior Visit RateRatio OVERALL19.7%3.7%5.4 < 10 months 21.5%4.3% months* 12.8%2.6%4.9 > 14 months 13.2%3.8%3.4 *10-14 months analogous to “routine” or annual visit.

Limitations Unable to distinguish between new infections, reinfections, and persistent infections. Unable to distinguish between new infections, reinfections, and persistent infections. Women do not get all of their care at FP clinics, and therefore, we may be missing additional infections diagnosed in other settings. Women do not get all of their care at FP clinics, and therefore, we may be missing additional infections diagnosed in other settings. Many clinics do not use unique identifiers, and therefore patients from those clinic sites are excluded from the analysis. Many clinics do not use unique identifiers, and therefore patients from those clinic sites are excluded from the analysis. Data on clinical signs and risk history are collected inconsistently, and could not be used in the model. Data on clinical signs and risk history are collected inconsistently, and could not be used in the model.

Conclusions Women screened for chlamydia in family planning clinics who have an initial positive test are at high risk for subsequent infection. Women screened for chlamydia in family planning clinics who have an initial positive test are at high risk for subsequent infection. Chlamydia positivity among women previously infected is higher among young women and women from urban areas, reflecting the higher prevalence of disease in these populations. Chlamydia positivity among women previously infected is higher among young women and women from urban areas, reflecting the higher prevalence of disease in these populations. The relative risk of reinfection is greater among women over age 30, perhaps reflecting the higher risk status of women over 30 who are infected at all. The relative risk of reinfection is greater among women over age 30, perhaps reflecting the higher risk status of women over 30 who are infected at all.

Conclusions Chlamydia positivity among women tested less than a year after a previous infection was higher than that of women tested at an annual visit. Chlamydia positivity among women tested less than a year after a previous infection was higher than that of women tested at an annual visit. The relative risk of reinfection was the same for women tested before or at an annual visit, while those tested less often had a lower relative risk of reinfection. The relative risk of reinfection was the same for women tested before or at an annual visit, while those tested less often had a lower relative risk of reinfection.

Implications for the Screening Program Are there high levels of repeat chlamydia infections among women attending family planning clinics? Are there high levels of repeat chlamydia infections among women attending family planning clinics?  Yes – With an overall reinfection rate of 19.7%, the data support the rescreening of women testing positive for chlamydia who return for care in FP clinics. Should providers screen women only once a year? Should providers screen women only once a year?  No – Based on substantial chlamydia positivity among women tested less than 10 months from a prior test, rescreening is warranted even if the next visit is within a year of a prior visit.

Implications for the Screening Program Should providers stop screening women who tested negative on a prior visit? Should providers stop screening women who tested negative on a prior visit?  No - Since chlamydia positivity for women testing negative at a prior visit was greater than 2% overall within the regional screening criteria (age <30), continued screening of all young women attending family planning clinics in Region III is warranted.

Implications for Future Research Since most project areas in Region III have switched to more sensitive amplified testing methods since 1998, this analysis should be performed on more recent data. Since most project areas in Region III have switched to more sensitive amplified testing methods since 1998, this analysis should be performed on more recent data. Future studies of repeat infection may be useful in evaluating current Region III enhanced partner management strategies. Future studies of repeat infection may be useful in evaluating current Region III enhanced partner management strategies.