BASELINE ASSESSMENT OF CHLAMYDIA REINFECTION IN

REGION VIII FAMILY PLANNING CLINICS FOR 2004-2005

Hamby, Y, JSI Research & Training Institute Donovan, KA, Variable Solutions

Region VIII IPP Data Workgroup

Background

• Region VIII Infertility Prevention Project

• Chlamydia Reinfection

OBJECTIVES

1. Calculate the incidence of Chlamydia reinfection in women who screened for Chlamydia in Family Planning Clinics in Region VIII over a two year period (2004 and 2005).

2. To determine if women with greater than one visit and positive Chlamydia result has a higher reinfection rate than women with greater than one visit and negative Chlamydia result.

METHODS

Analysis was conducted on 93,660 testsperformed on women from 2004 to 2005 inColorado, Montana, North Dakota, SouthDakota, Utah, and Wyoming.

Positivity rates for women with prior positiveChlamydia tests were compared to those fromwomen with prior negative tests.

Records for Analysis

253,876 Records

(2004-2005)

Exclude Males

Exclude Lab 7

Exclude non Family Planning Clinics

Exclude Equivocals

Records Used for Analysis

93,660

• Time since prior visit• Project area where patient was tested• Unique patient identifier (Soundex Code +

DOB)• Age• Race/Ethnicity• Positive at their first visit• Negative at their first visit• Number of tests

Variables Included in the Analysis

Group 1 = +CT result at first visit* and > 1 visit.

Group 2 = -CT result at first visit* and > 1 visit.

Groups

*First visit is the first time appearing in database.

Groups

Jan 04 July 04 Jan 05 July 05 Dec 05

Test1 (+CT) … Test2 (+CT) Group 1

Test1 (-CT) … Test2 (+CT) Group 2

First visit is the first time appearing in database.

Test1 (+/-CT) ………… Test2 (+/-CT) Not included in analysis

• The Incidence Rate is defined as a new case of Chlamydia no earlier than 3 months after the initial result and no later than 9 months after initial results.

• If the amount of time between initial result and retest is 10-18 months this is considered an annual visit test.

Incidence Definition

• Calculated the Risk Ratio for women testing more than once 3-9 months after their first test during 2005-2005.

• Group 1 = +CT result at first visit and > 1 visit.• Group 2 = -CT result at first visit and > 1 visit.

Incidence of Chlamydia Infection in group 1 (+CT)

Risk Ratio = Incidence of Chlamydia Infection in group 2 (-CT)

Analysis

State Distribution

Percent of Chlamydia Tests by State Region VIII, 2004-2005

37%

27%

13%

7%

8%8%

Colorado Montana N. Dakota S. Dakota Utah Wyoming

RESULTS• 13,838 women were tested more than once

Graph 1: Age breakdown of women with initial CT infection attendingFP clinics and percent second infection, Region VIII IPP, 2004-05

0.0%20.0%40.0%60.0%80.0%

100.0%

Total <15 15-17 18-19 >20

% of Clients %2nd Infection

RESULTS

Graph 2: Race/Ethnicity of women with initial CT infection attending FPclinics and percent second infection, Region VIII IPP, 2004-05

0.0%20.0%40.0%60.0%80.0%

100.0%

Total White Black AmericanIndian

Asian Hispanic

% of Clients % 2nd Infection

• Women who had repeated Chlamydia tests during the study period averaged 2.5 (range=2-9) tests per woman.

Graph 3: Number of visits for clients with initial CT infection attending FP clinics and percent second infection, Region VIII IPP, 2004-05

0.0%20.0%40.0%60.0%80.0%

100.0%

Total 2 visits 3 visits 4 visits 5 visits 6+ visits

% of Clients % 2nd Infection

RESULTS

• Incidence Rate (-CT) = 0.87

• Incidence Rate(+CT) = 3.55

• Risk Ratio +CT/-CT = 4.06

RESULTS

The incidence of Chlamydia positivity in women with an initial positive Chlamydia test result is 4 times higher than the incidence

of Chlamydia positivity in women with an initial negative Chlamydia test result!

• Women with an initial +CT result have a Chlamydia positivity rate higher than the CDC goal of 3% or lower.

Overall 2nd infection rate was 23.7% and was higher among: racial/ethnic minorities, women whose first IPP clinic visit was age < 15 years.

CONCLUSIONS

• Why do women with an initial +CT result have a higher incidence of Chlamydia 3–9 months after their initial test?

– Due to untreated partners

– Due to the same infection

DISCUSSION

• Do these data support retesting women for Chlamydia?– Yes – With a Risk Ratio of 4.06 for reinfection, the data support the

rescreening of women testing positive for Chlamydia who return for care in FP clinics.

• When should retest occur?– 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.

DISCUSSION

• Passive follow-up, particularly for women where selective screening criteria included additional measures beyond age, impacts likelihood of re-screening.

• Substantial variation in visit patterns affects detection of second infections and time to 2nd infection.

• Only have test records for clients who returned to IPP clinics. Lack data on visits outside IPP.

LIMITATIONS

1. Cates W Jr, Brunham RC. Sexually transmitted diseases and infertility. In: Holmes KK, Sparling PF, Mardh P-A, et al., eds. Sexually Transmitted Disease, 3rd ed. New York: McGraw-Hill, 1999; 1079–1087.

2. Hosenfeld CB et al. Repeat Infection With Chlamydia and Gonorrhea Among Females: A systematic Review of the Literature. Sex Transm Dis 2009; 36(8):478-489.

3. Hamby Y and Region VIII IPP Data Workgroup. Using the Soundex Function to Track Chlamydia Reinfection Rates in the Region VIII Infertility Prevention Project. National STD Prevention Conference, 2008. (Poster)

REFERENCES