Sexually Transmitted Diseases:
Screening for Chlamydia trachomatis Using Self-Collected Vaginal Swabs at a Public Pregnancy Termination Clinic in France: Results of a Screen-and-Treat Policy
Lavoué, Vincent MD*,†; Vandenbroucke, Laurent*,†; Lorand, Sophie MD*,†; Pincemin, Patrick*; Bauville, Estelle MD†; Boyer, Laurence MD†; Martin-Meriadec, Daniel MD†; Minet, Jacques PhD‡; Poulain, Patrice MD*,†; Morcel, Karine MD, PhD*,†
From the *Faculté de Médecine, Université de Rennes 1, Rennes, France; †Département de Gynécologie et d'Obstétrique, CHU Rennes, Rennes, France; and ‡Département de microbiologie, CHU Rennes, Rennes, France
The authors thank American Journal Experts for editing the manuscript.
V.L. and L.V. have both contributed equally to his work.
Correspondence: Vincent Lavoué, MD, Service de gynécologie et d'obstétrique, CHU Hôpital sud, 16 Bd de Bulgarie, BP 90347, F-35 203 Rennes Cedex 2, France. E-mail: email@example.com.
Received for publication November 3, 2011, and accepted March 8, 2012.
Objective: To assess the prevalence of Chlamydia trachomatis (CT) infection and the risk factors for CT infection among women presenting for abortion at a clinic in France.
Methods: Women seeking surgically induced abortions were systematically screened by PCR on self-collected vaginal swabs between January 1, 2010, and September 30, 2010. CT-positive women were treated with oral azithromycin (1 g) before the surgical procedure.
Results: Of the 978 women included in the study, 66 were CT positive. The prevalence was 6.7% (95% confidence intervals [CI] 5.1%–8.3%). The risk factors for CT infection were the following: age <30 years (Odds ratio [OR]: 2.0 [95% CI: 1.2–3.5]), a relationship status of single (OR: 2.2 [95% CI: 1.2–4.0]), having 0 or 1 child (OR: 5.2 [95% CI: 2.0–13.0]), not using contraception (OR: 2.4 [95% CI: 1.4–4.1]), and completing 11 weeks or more of gestation (OR: 2.1 [95% CI: 1.3–3.6]). Multiple logistic regression indicated that 4 factors—having 0 or 1 child, a single relationship status, no contraceptive use, and a gestation of 11 weeks or more—were independently associated with CT infection. The rate of postabortion infection among all patients was 0.4% (4/978).
Conclusions: These results reveal a high prevalence (6.7%) of CT-positive patients among French women seeking induced abortions. Because it is not common practice to screen the general population for CT, screening before induced abortions seems relevant. A cost-effectiveness study is required to evaluate this screen-and-treat policy.
Induced abortion is one of the most common surgical procedures worldwide, with approximately 189,000 procedures per year in England and Wales,1 >1 million in the United States,2 and 220,000 in France.3 Postabortion infections occur in 0.6% to 4.7% of cases.4–6 Some studies gave wide range of postabortion infections largely because of inconsistent definitions of postabortal infection.6 Postabortion infection can cause, when untreated, long-term serious sequelae, including tubal infertility, chronic pain, and ectopic pregnancy.7
When a single organism is identified in postabortal pelvic inflammatory disease (PID), it is most often Chlamydia trachomatis (CT). Studies show that as many as 20% to 63% of women who had CT-positive test results at the time of their surgically induced abortions developed PID, compared with only 1.6% of CT-negative women.8,9 Early first-trimester medical abortion is a noninvasive procedure with a low infection rate (approximately 0.3%), requiring no systematic antibiotic prophylaxis.6,10,11
Appropriate preoperative antibiotic prophylaxis is likely to reduce the incidence of postabortion PID to <1%.6,12,13 To prevent postabortion infection, both a screen-and-treat policy and universal antibiotic prophylaxis are in use. Recently, the Society of Family Planning recommended the routine use of antibiotic prophylaxis before surgical abortion.6 Universal antibiotic prophylaxis is more cost effective than a screen-and-treat strategy,14,15 but the benefits and costs of each strategy (universal antibiotic prophylaxis or screen-and-treat policy) depend on the prevalence of CT among those seeking induced abortions. For universal antibiotic prophylaxis, the more the prevalence rate decreases, the more the infectious risk decreases, and the more the number of women who need to receive antibiotics increases, while the risks of side effects and adverse reactions from the antibiotics persist.6 However, the additional cost of a screen-and-treat strategy, compared with the universal antibiotic prophylaxis, is mainly because of the cost of screening tests to detect CT. Thus, a risk-based algorithm may be a more cost-effective alternative. In France, the CT prevalence in people aged 18 to 44 years was estimated at 1.6% (95% confidence interval [CI]: 1.0%–2.5%) for women,16 but fewer data on the prevalence of CT are available for the population of women requesting induced abortion.
Thus, the aim of this study was to determine the prevalence of CT infection among women who underwent induced abortions in France and to identify the factors associated with a positive CT test so as to identify those for whom the screening test will be most relevant.
MATERIALS AND METHODS
We conducted a retrospective cohort study on patients who underwent an elective first-trimester surgical abortion. Using the pregnancy termination clinic database, we identified medical care of 1000 consecutive women requesting a surgically induced abortion at the pregnancy termination clinic of the Rennes teaching hospital between January and September 2010. This public clinic performed 70% of the induced abortions in the district named Ille et Vilaine, France, which accounts for 1.5% of the French population.
Patient and Specimen Collection
Patients who presented seeking surgically induced abortions were offered a test for CT infection, free of charge. Verbal informed consent was obtained from all of those who agreed to perform this test for CT infection. Specimens were collected from these women during the nurse interview, a few days before the surgically induced abortion was scheduled to occur. Patients were asked to provide self-collected swabs. Patients were instructed to insert the swab 5 cm into the vagina and rotate before removing and placing it into the specimen tube. The swabs and transport media were supplied from the RDI-Microtest M4RT kit (Remel, Dardilly, France).
Specimen Transport and Testing
The samples were stored at 4°C to 8°C until the end of the day on which they were collected, and then they were frozen in the laboratory. DNA extractions were performed with a Magtration System 12GC work station and a MagDEA DNA 200 (GC) reagents kit (Bionobis, Saint Quentin en Yvelines, France). DNA extracts were submitted to real-time polymerase chain reaction (PCR) amplification directed to the CT cryptic plasmid pLGV440 in a 5′nucleotidase assay with primers 5′-TGT AAC AAC AAG TCA GGT TGC-3′ and 5′-TGC ACG AAG TAC TCT AGG AGT-3′ and probe 5′-(6FAM) CAT AGC ACT ATA GAA CTC TGC AAG CCT (TAMRA)(p)-3′. Human albumin gene detection was included for each extract to assess both the absence of PCR inhibitors and the quality of the samples. Negative (ultrapure water) and positive (CT DNA) controls were included in each reaction plate. Amplifications were performed using the LightCycler 480 Probes Master 2X master mix and the LC480 thermal cycler (ROCHE DIAGNOSTICS, Neuilly sur Seine, France). The result of the test was reported 1 to 3 days after screening.
Management of CT-Positive Women
Patients were informed of positive results on the day of the surgically induced abortion by a clinic health care worker who also gave oral and written general information on CT. Women were advised to contact their sexual partner(s) so that they could seek treatment for CT (a prescription for 1 g of azithromycin was given for each partner). Infected women were treated with single-dose oral azithromycin (1 g) 1 hour before surgically induced abortion.
Data Collection and Analysis
The medical records of the patients were reviewed. Sociodemographic data were collected, including age, marital status, parity, reason for pregnancy termination, length of gestation at termination, number of previous pregnancy terminations, and use of reliable contraception. Gestational sac diameter and crown-rump length measurements by ultrasonographic examination have been used to assess gestational age. Data collected also included behavioral details and relevant clinical data. In addition, history of previous PID was noted. Outcomes were obtained from outpatient records collected 2 to 3 weeks after surgically induced abortion. Postabortion consultations were systematically scheduled.
The main outcome measure was the prevalence of CT infection. The secondary outcome measure was the risk factor(s) for CT infection among women seeking surgical abortions. The third outcome measure was the rate of postsurgical induced abortion infection associated with our screen-and-treat policy. Postsurgical abortion infection was defined as fever and/or use of antibiotics for suspicious endometritis between the surgically induced abortion and the outpatient follow-up 2 to 3 weeks after the procedure.
Participants were assigned a study number, and data were entered into a Microsoft (Redmond, WA) Excel spreadsheet. Analyses were performed with R statistical software available online at http://www.r-project.org.
The overall prevalence of CT infection (primary outcome measure) was estimated with its associated 95% CI from women testing positive for CT infection by PCR as a proportion of all women providing a vaginal swab with an interpretable PCR test for CT infection. The age-specific prevalences for CT infection were calculated, and demographic and behavioral variations in prevalence were also explored.
Univariate analysis was performed using the χ2 test and Fisher exact test. A P value of <0.05 was considered statistically significant. Stepwise multiple logistic regression was performed to obtain an adjusted odds ratio (OR) for each sociodemographic characteristic. The unadjusted ORs (95% CI) associated with these risk factors were also calculated. The sensitivity of a risk factor was defined as the probability of the risk factor being present among infected women, and represents the proportion of infected women who would be detected by screening using that risk factor. The specificity of a risk factor was defined as the probability of the risk factor being absent among uninfected women, and represents the proportion of uninfected women who would avoid screening if it was based on that risk factor.
This study was approved by the Institutional Review Board of the French college of obstetricians and gynecologists (Comité d'Ethique de la Recherche en Obstétrique et Gynécologie) (CEROG-2011-GYN-08–03).
During the period of investigation, of the 1277 women presenting at the clinic for induced abortion, 1000 women underwent a surgical abortion. Nine hundred eighty (98%) accepted a swab for use in testing. We excluded 2 patients whose sample results were uninterpretable. Finally, 978 women were enrolled (Fig. 1). The population characteristics are presented in Table 1. Mean age was 26.6 ± 7.0 years (range: 14–48). Twenty percent of the women had universal health care coverage or state medical aid, although only 4% of the French general population had one or the other. Forty-eight percent of the enrolled women had one or more child, and 29% of them had previous induced abortions. Nearly half of women used no contraception.
Prevalence of CT Infection and Factors Associated With It
CT infection was detected in 66 women. The prevalence of infection among women pursuing surgical abortions was 6.7% (95% CI: 5.1%–8.3%). Univariate analysis (Table 2) found that CT infection was associated with age <30 years (OR: 2.0 [95% CI: 1.2–3.5]), a relationship status of single (OR: 2.2 [95% CI: 1.2–4.0]), having 0 or 1 child (OR: 5.2 [95% CI: 2.0–13.0]), not using contraception (OR: 2.4 [95% CI: 1.4–4.1]), and 11 or more weeks of gestation (OR: 2.1 [95% CI: 1.3–3.6]) .
Multivariate analysis confirmed that having 0 or 1 child, a relationship status of single, not using contraception, and a gestation of 11 weeks or more were independently associated with CT infection (P < 0.05) (Table 3).
Predictive Ability of Signs for CT Infection
The sensitivities and specificities of selected variables for the detection of CT in this population are shown in Table 4. Screening women solely on the basis of whether they have 0 or 1 child would have required 72% of the women seeking a surgical abortion to be screened to detect >92% of the CT infections.
Rate of Postsurgical Infection
Of the 978 women who underwent surgical abortion, only 497 (50.8%) returned for their scheduled postabortion consultation. Postsurgical infection was detected in 4 women (3 in women who returned and 1 in women who did not return and treated in other clinic). Two women presented with fever and were treated with antibiotics without further surgical intervention. Two women presented with pelvic pain and vaginal discharge without fever and required antibiotic treatment without further surgical intervention. The rate of postsurgical CT infection was 0.4% among all patients (4/978). The rate of postabortion infection is 1.5% for CT-positive patients and 0.3% for CT-negative patients (NS).
The prevalence of CT infection among the women in this study was 6.7%, and it increased to 9% for women aged <25 years. Our data are consistent with one previous study in France.17 However, this previous study evaluated the prevalence of CT infection only in patients aged 15 to 26 years. We also identified a simple criterion (having 0 or 1 child) that may allow detection of >90% of women with CT infection and may avoid screening nearly 30% of those seeking surgical abortions. To our knowledge, this has not previously been described. Finally, we show a low rate (0.4%) of postabortion infection with our screen-and-treat policy based on the oral administration of azithromycin 1 hour before the surgical procedure for women with CT infections.
Our study has several limitations because of its retrospective nature. The absence of a control group, one without a screening program or systematic prophylactic strategy, made it impossible to establish a baseline rate of postabortion infection. Therefore, we can neither assess the effects of our procedures on risk reduction nor comment on the cost-effectiveness of universal screening and therapeutic treatment in this population. Nevertheless, our rate of postabortion infection is low, and it is in agreement with previous studies of systematic antibiotic prophylaxis (range: 0.6%–2.1%).6 Thus, we conclude that a screen-and-treat policy using azithromycin before a surgical abortion procedure is an efficient method. Even if 1 or more postabortion infections occurred without our knowledge, because of our low follow-up rate (51%), our experience and community visibility as a major provider of abortion services for >30 years make it likely that we would have been contacted about a noteworthy complication in a nonreturning patient. Our follow-up rate of 51% is similar to that reported in similar clinics in France (25%–74%)18,19 and those in others western countries.20,21 The different follow-up rates depend on the survey policies of the abortion clinics.
We chose self-collected vaginal swabs because nurses cannot examine patients, but, in our clinic, they are the first health workers to meet women seeking induced abortions. A sample collected early makes detection before the surgical procedure possible, and thus antibiotic treatment is an option. Previous studies have demonstrated that results obtained with vaginal swabs collected by the patients were comparable in both sensitivity and specificity with the results obtained with specimens collected by clinicians and with the results obtained with cervical swabs, which are currently considered to be the gold standard.22 Furthermore, women are significantly more likely to choose a self-administered swab over a clinician-administered swab for CT testing.23,24 Our findings show that the prevalence of CT infection among women seeking surgical abortions at our clinic in France is 6.7%, which is similar to the 6% to 8% prevalence among women requesting induced abortions in the United Kingdom.9,14,25,26 However, at our clinic in France, we observed a high prevalence of CT infection (6.8%) for women aged 25 to 29 years versus 2.9% to 3.9% in United Kingdom.25,26 Similar to other countries, we observed a high prevalence (approximately 10%) for women aged <25 years. Our findings, based on a large, urban, public pregnancy termination clinic, update disease prevention information and may help to establish sexual and reproductive health strategies in France. Analyses of the opportunistic screening of women attending health care clinics or specific high-risk groups have shown such procedures to be cost-effective for infections with prevalences between 2% and 8%.25, 27–30 Thus, screening for CT in induced abortion clinics, as advocated by the French Health Authority (Haute Autorité de Santé), must be offered, as it is likely to bring significant benefit to patients, their partners, and, indirectly, to the wider population. Selective screening has clear clinical and economic benefits compared with both not screening and universal screening.25 To increase the cost-effectiveness of screening for CT, highly sensitive criteria must be defined to decrease the number of women who must be tested. Our findings provide such a criterion: having 0 or 1 child allows for the detection of >90% of women with CT infection and prevents the screening of nearly 30% of those seeking surgical abortions. Other useful criteria would offer an alternative to systematic screening of the entire population while ensuring a decreased rate of postabortion infection. The use of prophylactic antibiotics for all surgical abortions occurring during the first trimester has been recommended by several medical societies to minimize postabortion infections.6 This strategy is the most cost effective.14 However, this strategy does not help to prevent the long-term morbidity associated with CT infection.15 Thus, an efficient nomogram with high sensitivity and high specificity must be developed. Of course, if this policy is implemented, strategies for ensuring effective partner notification and treatment for CT infection should also be explored.
These results provide the first prevalence data for CT infection in French women seeking induced abortions. The high rate (6.7%) of CT found in this at-risk population points to a possible need for the availability of CT tests in French clinical practice. Further research is necessary to determine an efficient nomogram that will identify those at high risk of CT infection, reduce the number of tests administered, and increase the cost-effectiveness of the screen-and-treat policy. This policy results in a low rate of postabortion infection and potentially prevents the long-term morbidity associated with CT infection.
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