Re-testing for Chlamydia trachomatis Infection in Massachusetts Family Planning Clinics Marie E. Caggiano, William G. Dumas, Thomas E. Bertrand, Katherine K. Hsu, Sylvie Ratelle

Abstract Background Because a high prevalence of chlamydia re-infection has been observed in women following treatment for chlamydia infection, the CDC has recommended re-testing of all women approximately 3 months after treatment for chlamydia infection. Little is known about factors influencing a womans return for re-testing. Objective To examine factors associated with chlamydia re-testing after treatment for chlamydia infection. Methods A case was defined by first positive chlamydia test in a woman seen between 1/1/05-12/31/05 at one of 8 Massachusetts family planning organizations. Data available for review included age at diagnosis, clinic organization, race/ethnicity, and history of prior chlamydia infection. Multivariate logistic regression was performed to identify factors associated with chlamydia retesting 3-<12 months after the initial positive test. Results Of 402 chlamydia cases in women identified during the study period, 116 (29%) had re-testing within years old. The two clinic organizations handling highest number of chlamydia infections re-tested 62/161 (39%), versus 9/56 (16%) in two clinic organizations with lowest number. Younger age (OR 1.8, 95% CI ) and highest number (OR 3.3, CI ) were associated with retesting in a logistic regression model including age, race/ethnicity, clinic organization, and prior history of chlamydia infection. No significant associations with re-testing were found with race/ethnicity or prior history of chlamydia infection. Conclusions Repeat chlamydia infection was common in women re-tested for chlamydia 3-<12 months after incident chlamydia infection. Younger age and certain clinic organizations were associated with greater chlamydia re- testing amongst women seen at Massachusetts family planning organizations.

Background Recurrent or persistent chlamydia infection occurs in 10-15% of cases 1 –Some studies report rates as high as 15-38% 2,3 –Most often related to re-exposure from an untreated sexual partner 4 –Associated with increased rates of pelvic inflammatory disease and hospitalization for related complications 5 Follow-up screening recommended since 1996 for all women diagnosed with chlamydia infection 1 –Ideally performed 3-4 months after completion of antibiotic treatment –Offered at any visit occurring 3-12 months after treatment –Differentiated from test of cure (which is done 3-4 weeks following treatment and indicated only in specific circumstances) Risk factors associated with recurrent infection have been well studied, but little is known about factors that influence attendance for follow-up screening

Methods (1) Data abstraction –Review of records of women tested at Massachusetts family planning clinics participating in the Infertility Prevention Project (IPP) –Case defined by positive chlamydia test (strand displacement assay, BD Probetec ET; Becton Dickinson, Sparks, MD) between 01/01/05 to 12/31/05 –Each case reviewed for age at initial diagnosis, clinic site, race/ethnicity, history of prior chlamydia infection reported in Massachusetts, and chlamydia testing 3-12 months after initial diagnosis Age categorized into two groups –>18 years –< 18 years Race/ethnicity categorized into four groups –White, non-Hispanic –Black non-Hispanic –Hispanic –Other, non-Hispanic –Unknown ethnicity Clinics categorized based on volume of positive chlamydia tests –8 clinic organizations categorized into 4 sub-groups based on number of positive chlamydia tests handled

Methods (2) Data analysis –Bivariate analysis and multivariate logistic regression used to examine factors associated with re-testing within 3-12 months of initial diagnosis –SAS version 9.1 (SAS Institute, Inc., Cary, NC) utilized –Waiver granted by Massachusetts Department of Public Health (MDPH) Human Research Review Committee (HRRC)

Figure 1 Proportion of Women Re-tested for Chlamydia Within 3-12 Months of Initial Diagnosis N=402

Figure 2 Proportion of Positives in Women Re-tested for Chlamydia Within 3-12 Months of Initial Diagnosis N=116

Figure 3a: Percent of Women Re-tested for Chlamydia by Age Women < 18 yearsWomen > 18 years Percent Re-tested

Figure 3b: Percent of Women Re-tested for Chlamydia by Race/Ethnicity Percent Re-tested

Figure 3c: Percent of Women Re-tested for Chlamydia by History of Prior Chlamydia Infection HistoryNo history Percent Re-tested

Figure 3d: Percent of Women Re-tested for Chlamydia by Volume of Positives at Clinic Site Percent Re-tested Clinic Sites by Volume of Positive Chlamydia Tests

Table 1. Association Between Variables and Chlamydia Re-testing 3-12 Months After Initial Diagnosis *Odds ratios adjusted for age category, history of prior infection, race/ethnicity, and volume of testing at clinic site

Conclusions Among women tested for chlamydia at Massachusetts family planning clinics, approximately 29% were re-tested within 3-12 months of initial diagnosis –25% of women re-tested for chlamydia had recurrent infection Age < 18 years and highest clinic positivity were associated with greater rates of re-testing

Limitations Findings based on retrospective record review with only a limited number of factors available for analysis

Implications Further study is needed to identify additional factors that influence re- testing rates and examine strategies for increasing rates of re-testing In 2006, MDPH began a monthly report-back system to notify clinics of positives and facilitate call backs for re-testing –Analyses underway to evaluate effectiveness of this intervention

References 1.Centers for Disease Control and Prevention. Sexually transmitted diseases treatment guidelines, MMWR 2006;55(RR-11): Xu et al. Repeat chlamydia trachomatis infection in women: Analysis through a surveillance case registry in Washington state Am J Epidemiol 2000;152: Blythe et al. Recurrent genitourinary chlamydial infections in sexually active female adolescents. J Pediatr 1992;121: Peterman et al. High incidence of new sexually transmitted infections in the year following a sexually transmitted infection: A case for re- screening. Ann Intern Med 2006;145: Hillis et al. Recurrent chlamydial infections increase risk of hospitalization for ectopic pregnancy and pelvic inflammatory disease. Am J Obstet Gynecol 1997;176:

VariableWomen Re- tested N=116 ( 29%) Women Not re- tested N=286 Total to N= 402 Women Re-tested N=148 ( 43%) Women Not Re- tested N= 192 Total to N= 340 Age >18 years73 ( 25%) ( 39%) <18 years43 ( 41%) ( 51%)56115 Race/ethnicity White non- Hispanic 50 (26%) ( 48%) 73 ( 46%) ( 46%) Black non- Hispanic 21 ( 35%) 3960 ( 15%) 35 ( 43%) 4681 ( 24%) Hispanic26 (36%)4672 ( 18%)17 ( 37%)2946 ( 13%) Other non- Hispanic 4 ( 20%) 1620 ( 5%) 7 ( 53%) 613 ( 4%) Unknown15 ( 37%)4257 ( 14%)16 ( 37%)2743 ( 13%)