Repeat Chlamydial Infections in Region III Family Planning Clinics:

Implications for Screening Programs

Pamela G. Nathanson, Family Planning Council, Inc.Pamela G. Nathanson, Family Planning Council, Inc.Mary Dupuis Sammel, ScD and Mary Dupuis Sammel, ScD and Michelle Berlin, MD, MPHMichelle Berlin, MD, MPHCenter for Clinical Epidemiology and BiostatisticsCenter for Clinical Epidemiology and BiostatisticsUniversity of Pennsylvania Medical CenterUniversity of Pennsylvania Medical CenterPhiladelphia, PAPhiladelphia, PA

Background The Region III Chlamydia Project has provided The Region III Chlamydia Project has provided

chlamydia screening and treatment for women as part of chlamydia screening and treatment for women as part of CDC’s National Infertility Prevention Program (IPP) CDC’s National Infertility Prevention Program (IPP) since 1994.since 1994.

All women under age 30 who undergo a pelvic exam are All women under age 30 who undergo a pelvic exam are routinely screened for chlamydia in family planning (FP) routinely screened for chlamydia in family planning (FP) clinics. clinics.

Approximately 300,000 women are screened annually Approximately 300,000 women are screened annually throughout the 8 project areas (Baltimore, Delaware, throughout the 8 project areas (Baltimore, Delaware, Maryland, Pennsylvania, Philadelphia, Virginia, West Maryland, Pennsylvania, Philadelphia, Virginia, West Virginia, Washington DC).Virginia, Washington DC).

Screening Program Issues Anecdotal reports from providers suggested high Anecdotal reports from providers suggested high

levels of repeat chlamydia infections among levels of repeat chlamydia infections among women attending family planning clinics.women attending family planning clinics.

Increased efforts around partner management were Increased efforts around partner management were initiated, with little concrete data on repeat initiated, with little concrete data on repeat infection rates.infection rates.

Some providers wanted to avoid repeat screenings Some providers wanted to avoid repeat screenings of women testing negative on prior visits, but had of women testing negative on prior visits, but had no data to support this change in screening no data to support this change in screening practices.practices.

Objectives

To determine rates of repeat infections To determine rates of repeat infections among women screened for chlamydia in among women screened for chlamydia in family planning clinics in Region III family planning clinics in Region III between 1996 and 1998.between 1996 and 1998.

To determine if a low-risk group could be To determine if a low-risk group could be identified that might not require repeat identified that might not require repeat screening over time.screening over time.

Methods

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

Description of Data

990,847 Number of records between 1996-1998

- 30,139 Excluded records from males

-161,327 Excluded records from non-family planning clinics

-247,698 Excluded records from 2 areas without unique Ids-----------551,683 Records from women with at least 1 visit

-354,889 Excluded records with only 1 visit----------196,794 Records for 85,175 women with multiple visits

-22,516 Records with discrepancies (mismatched age, etc.)---------- 174,278 Total records for 73,107 women

Methods

Positivity rates for women with prior Positivity rates for women with prior positive chlamydia tests were compared to positive chlamydia tests were compared to those for women with prior negative tests.those for women with prior negative tests.

Variables in the analysis included:Variables in the analysis included: ageage time since prior visittime since prior visit project area where patient was tested.project area where patient was tested.

Number of Visits Per Woman# of Visits# of Visits FrequencyFrequency %%

22 53,77553,775 73.673.6

33 14,02014,020 19.219.2

44 3,4363,436 4.74.7

55 1,0961,096 1.51.5

6-76-7 590590 0.80.8

8-98-9 139139 0.20.2

10-1210-12 4646 <0.1<0.1

13-1613-16 55 <0.1<0.1

TOTALTOTAL 73,10773,107 100.0100.0

Demographic DistributionTOTALTOTAL 73,10773,107 100.0%100.0%PROJECT AREAPROJECT AREA NN PercentPercentBaltimoreBaltimoreDelawareDelawareMarylandMarylandPennsylvaniaPennsylvaniaPhiladelphiaPhiladelphiaVirginiaVirginiaWashington DCWashington DCWest VirginiaWest Virginia

2,0482,0486,2186,218

0031,92031,92021,58921,58910,47910,479

85385300

2.8%2.8%8.5%8.5%0.0%0.0%

43.7%43.7%29.5%29.5%14.3%14.3%

1.2%1.2%0.0%0.0%

AGE (years)AGE (years) NN PercentPercent12-1412-1415-1915-1920-2420-2425-2925-2930+30+

1,3461,34623,93923,93922,98222,98214,48714,48710,12310,123

1.8%1.8%32.8%32.8%31.5%31.5%19.9%19.9%13.9%13.9%

Infection Rates by Infection Status at Prior Visit

Infected atInfected at

Prior VisitPrior Visit

Uninfected at Uninfected at Prior VisitPrior Visit

Rate RatioRate Ratio

OVERALLOVERALL 19.7%19.7% 3.7%3.7% 5.45.4Baltimore Baltimore n=2,048n=2,048 20.6%20.6% 3.5%3.5% 5.95.9Delaware Delaware n=6,218n=6,218 13.6%13.6% 3.6%3.6% 3.73.7Pennsylvania Pennsylvania n=31,920n=31,920 13.1%13.1% 1.8%1.8% 7.27.2Philadelphia Philadelphia n=21,589n=21,589 25.7%25.7% 6.1%6.1% 4.24.2Virginia Virginia n=10,479n=10,479 15.6%15.6% 4.1%4.1% 3.83.8Wash DC Wash DC n=853n=853 9.3%9.3% 2.7%2.7% 3.43.4

Infection Rates by Infection Status at Prior Visit –By Age Group

Infected atInfected at

Prior VisitPrior Visit

Uninfected at Uninfected at Prior VisitPrior Visit

RateRate

RatioRatio

OVERALLOVERALL 19.7%19.7% 3.7%3.7% 5.45.412 – 14 yrs 12 – 14 yrs n=1,346n=1,346 22.4%22.4% 8.7%8.7% 2.62.615 – 19 yrs 15 – 19 yrs n=23,939n=23,939 23.5%23.5% 6.0%6.0% 3.93.920 – 24 yrs 20 – 24 yrs n=22,982n=22,982 18.0%18.0% 3.9%3.9% 4.64.625 – 29 yrs 25 – 29 yrs n=14,487n=14,487 14.8%14.8% 2.3%2.3% 6.56.530+ yrs 30+ yrs n=10,123n=10,123 11.7%11.7% 1.1%1.1% 10.810.8

Infection Rates by Infection Status at Prior Visit and Time Since Prior Visit

Infected atInfected at

Prior VisitPrior Visit

Uninfected at Uninfected at Prior VisitPrior Visit

RateRate

RatioRatio

OVERALLOVERALL 19.7%19.7% 3.7%3.7% 5.45.4< 10 months< 10 months 21.5%21.5% 4.3%4.3% 5.05.010-14 months*10-14 months* 12.8%12.8% 2.6%2.6% 4.94.9> 14 months> 14 months 13.2%13.2% 3.8%3.8% 3.43.4

*10-14 months analogous to “routine” or annual visit.

Limitations Unable to distinguish between new infections, Unable to distinguish between new infections,

reinfections, and persistent infections.reinfections, and persistent infections. Women do not get all of their care at FP clinics, and Women do not get all of their care at FP clinics, and

therefore, we may be missing additional infections therefore, we may be missing additional infections diagnosed in other settings.diagnosed in other settings.

Many clinics do not use unique identifiers, and Many clinics do not use unique identifiers, and therefore patients from those clinic sites are excluded therefore patients from those clinic sites are excluded from the analysis.from the analysis.

Data on clinical signs and risk history are collected Data on clinical signs and risk history are collected inconsistently, and could not be used in the model.inconsistently, and could not be used in the model.

Conclusions Women screened for chlamydia in family Women screened for chlamydia in family

planning clinics who have an initial positive planning clinics who have an initial positive test are at high risk for subsequent infection.test are at high risk for subsequent infection.

Chlamydia positivity among women Chlamydia positivity among women previously infected is higher among young previously infected is higher among young women and women from urban areas, women and women from urban areas, reflecting the higher prevalence of disease reflecting the higher prevalence of disease in these populations.in these populations.

The relative risk of reinfection is greater The relative risk of reinfection is greater among women over age 30, perhaps among women over age 30, perhaps reflecting the higher risk status of women reflecting the higher risk status of women over 30 who are infected at all.over 30 who are infected at all.

Conclusions

Chlamydia positivity among women tested Chlamydia positivity among women tested less than a year after a previous infection less than a year after a previous infection was higher than that of women tested at an was higher than that of women tested at an annual visit.annual visit.

The relative risk of reinfection was the The relative risk of reinfection was the same for women tested before or at an same for women tested before or at an annual visit, while those tested less often annual visit, while those tested less often had a lower relative risk of reinfection.had a lower relative risk of reinfection.

Implications for the Screening Program Are there high levels of repeat chlamydia infections Are there high levels of repeat chlamydia infections

among women attending family planning clinics?among women attending family planning clinics? Yes – With an overall reinfection rate of 19.7%, the Yes – With an overall reinfection rate of 19.7%, the

data support the rescreening of women testing positive data support the rescreening of women testing positive for chlamydia who return for care in FP clinics.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 No – Based on substantial chlamydia positivity

among women tested less than 10 months from a prior among women tested less than 10 months from a prior test, rescreening is warranted even if the next visit is test, rescreening is warranted even if the next visit is within a year of a prior visit.within a year of a prior visit.

Implications for the Screening Program Should providers stop screening women who Should providers stop screening women who

tested negative on a prior visit?tested negative on a prior visit? No - Since chlamydia positivity for women No - Since chlamydia positivity for women

testing negative at a prior visit was greater than testing negative at a prior visit was greater than 2% overall within the regional screening 2% overall within the regional screening criteria (age <30), continued screening of all criteria (age <30), continued screening of all young women attending family planning clinics young women attending family planning clinics in Region III is warranted.in Region III is warranted.

Implications for Future Research

Since most project areas in Region III have Since most project areas in Region III have switched to more sensitive amplified testing switched to more sensitive amplified testing methods since 1998, this analysis should be methods since 1998, this analysis should be performed on more recent data.performed on more recent data.

Future studies of repeat infection may be useful Future studies of repeat infection may be useful in evaluating current Region III enhanced in evaluating current Region III enhanced partner management strategies.partner management strategies.