Prevalence of Chlamydia trachomatis infections and specimen collection preference among women, using self-collected vaginal swabs in community settings

BACKGROUND: Chlamydia trachomatis is a common, often asymptomatic sexually transmitted infection. GOAL: The goal was to estimate the prevalence and predictors of C. trachomatis among young women using self-collected vaginal swabs, and the preferences of women and physicians for self-testing. STUDY DESIGN: A total of 514 attendees of university/college health clinics, adolescent birth control clinics, centers providing health services to homeless youth and adults (street health centers), a sexually transmitted diseases clinic, and family practices were tested by ligase chain reaction. Preference for self- versus provider-testing was examined. RESULTS: Prevalence was 6.0% and was highest (18.2%) in the street health centers. In multivariate analysis, only recent contact with someone with C. trachomatis infection was significantly associated with infection (odds ratio, 7.1; 95% confidence interval, 2.5-20.0). Most women (54.2%; 256 of 472) preferred self-sampling compared with physician sampling (15.9%; 75 of 472). The majority of physicians (75.0%; 9 of 12) reported at the start and end of the study that they would use vaginal swab self-sampling if available. CONCLUSIONS: Prevalence of infection in young women attending homeless youth organizations was high. Self-sampling was acceptable and could facilitate screening in high-risk women who do not regularly access health services.     

Cost-effectiveness of screening strategies for Chlamydia trachomatis using cervical swabs, urine, and self-obtained vaginal swabs in a sexually transmitted disease clinic setting

BACKGROUND: We evaluated the cost-effectiveness of Chlamydia screening strategies that use different methods of specimen collection: cervical swabs, urines, and self-obtained vaginal swabs. METHODS: A decision analysis was modeled for a hypothetical cohort of 10,000 per year of women attending sexually transmitted disease (STD) clinics. Incremental cost-effectiveness of 4 screening strategies were compared: 1) Endocervical DNA probe test (PACE2, Gen-Probe), 2) Endocervical AC2 (Aptima Combo 2, Gen-Probe), 3) Self-Obtained Vaginal AC2, and 4) Urine AC2. Sensitivities of the vaginal, urine, and cervical AC2 tests were derived from 324 women attending STD clinics. The primary outcome was cases of pelvic inflammatory disease prevented. The model incorporated programmatic screening and treatment costs and medical cost savings from sequelae prevented. RESULTS: Chlamydia prevalence in the sampled population was 11.1%. Sensitivities of vaginal, urine, and cervical AC2 were 97.2%, 91.7%, and 91.7%, respectively. The sensitivity of the DNA probe was derived from the literature and estimated at 68.8%. The self-obtained vaginal AC2 strategy was the least expensive and the most cost-effective, preventing 17 more cases of pelvic inflammatory disease than the next least expensive strategy. CONCLUSIONS: Use of a vaginal swab to detect Chlamydia in this STD clinic population was cost-saving and cost-effective.     

Internet-based screening for Chlamydia trachomatis to reach non-clinic populations with mailed self-administered vaginal swabs

BACKGROUND: Testing for Chlamydia trachomatis by nucleic acid amplification tests (NAATs) using self-collected vaginal swabs (VS) is acceptable and accurate. The objectives were to implement an educational Internet-based program for women to facilitate home screening, to determine whether women would request and use self-collected VS kits, to determine associated risk factors for infection, and to determine satisfaction with the process. METHODS: The website, www.iwantthekit.org, was designed to encourage women > or =14 years to obtain home-sampling kits. Kits could be obtained in the community, requested by Internet/e-mail, or telephone. Users mailed the self-collected VS to the laboratory. Swabs were tested by 3 NAAT assays. Respondents called for results. RESULTS: Forty-one of 400 (10.3%) women were chlamydia positive; 95.1% were treated. Questionnaires indicated 89.5% preferred self-collection, 93.5% rated collection easy/very easy, and 86.3% would use the Internet program again. Black race and age <25 years were associated independently with being chlamydia positive, while use of birth control and non-consensual sex were protective. Thirty-six of 41 (87.8%) positive samples were positive by all 3 NAATs, 5/41 (12.2%) were positive by only 2 NAATs, and none were positive by only 1 NAAT. The Internet/e-mail request method was better than the community pick-up approach because 97.2% of kit requests were e-mailed and 87.5% of kits returned for testing were e-mail requested. CONCLUSIONS: Women will use the Internet to request and use home-sampling kits for chlamydia. NAAT testing performed well on dry-transported VS. High prevalence was detected and questionnaires indicated high-risk sexual behavior.     

Cost-effectiveness of screening programs for Chlamydia trachomatis: a population-based dynamic approach

BACKGROUND: Models commonly used for the economic assessment of chlamydial screening programs do not consider population effects. GOAL: To develop a novel dynamic approach for the economic evaluation of chlamydial prevention measures and to determine the cost-effectiveness of a general practitioner-based screening program. STUDY DESIGN: The dynamic approach was used to estimate the cost-effectiveness of a screening program for the first 10 years of screening in The Netherlands. Screening involved a ligase chain reaction test on urine followed by standardized therapies and partner referral. Eligible persons were sexually active, 15 to 24 years, visited a general practitioner, and had no symptoms of sexually transmitted diseases. The heterosexual model population, which consisted of persons 15 to 64 years, had a total chlamydial prevalence of 4.1% before screening. Screening effects on chlamydial incidence were computed by using a population-based stochastic simulation model. Incidence data were connected with a decision analysis model to determine the health effects of the program. The net costs of the program were calculated (investment costs minus averted costs, in 1997 US$) from a societal perspective and expressed per major outcome averted (symptomatic pelvic inflammatory disease, chronic pelvic pain, ectopic pregnancy, infertility, neonatal pneumonia). RESULTS: Unlike the standard static approach, our model adequately addresses dynamic processes such as chlamydial transmission and the impact of screening programs on chlamydial incidence in the population. During the first 10 years of screening, the investigated program yields savings of US $492 or US $1,086 per major outcome averted, excluding or including indirect costs, respectively. These results depend on chlamydial prevalence and partner referral. CONCLUSIONS: The cost-effectiveness of chlamydial screening programs seems best to be determined by using dynamic modeling on a population basis. In addition to preventing negative health outcomes, the investigated screening program may save costs.     

Evaluation of self-collected versus clinician-collected swabs for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae pharyngeal infection among men who have sex with men

We evaluated self-sampling to detect pharyngeal Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infection among men who have sex with men attending a San Francisco STD clinic. The prevalence of pharyngeal NG and CT infection was 6.7% (32/480) and 1.3% (6/480), respectively. The percent agreement between self-collected and clinician-collected NG and CT specimens using nucleic acid amplification testing was 96.6% with a κ of 0.766 (95% confidence interval: 0.653-0.879) and 99.4% with a κ of 0.766 (95% confidence interval: 0.502-1.000), respectively. Acceptability was high among participants.     

Cost-effectiveness of screening swab or urine specimens for Chlamydia trachomatis from young Canadian women in Ontario.

BACKGROUND: Undetected and untreated Chlamydia trachomatis infections can result in a significant health burden. Diagnostic testing refers to tests performed on patients with symptoms, whereas screening refers to testing specimens in asymptomatic patients. The goal of diagnostic testing and screening programs are early identification of infections to prevent upper tract infection and transmission to other partners. GOAL: To compare the costs and outcomes of alternative diagnostic testing and screening programs for women ages 15 to 24 years in the province of Ontario, Canada. STUDY DESIGN: Using outcome probabilities from the literature and a consensus group, together with the costs from insurance billing, a decision analytic model was constructed to determine the baseline risk of C trachomatis and related sequelae. Seven diagnostic testing and screening programs were compared over a 10-year period. The programs compared included the use of nucleic acid amplification assays collected from urine or endocervical swab specimens. RESULTS: Largely because of lower sensitivity the urine-based testing or screening programs were dominated by the swab-based programs. The move from swab-based testing to a swab-based screening program for high-risk women costs $1873 per case of C trachomatis averted. Expanding the program further to include all women in Ontario between 15 and 24 years of age is considerably more costly at $5990 per case averted. CONCLUSIONS: It is more costly and more effective to screen and treat high-risk women ages 15 to 24 years for C trachomatis than to perform only swab-based diagnostic testing on symptomatic women. Expanding the screening program to include all women ages 15 to 24 years is considerably more expensive and only moderately more effective than screening only high-risk women.     

Cost-effectiveness analysis of screening adolescent males for Chlamydia on admission to detention

BACKGROUND: Chlamydia trachomatis infections can lead to serious and costly sequelae. Because chlamydia is most often asymptomatic, many infected youth do not seek testing. Entry to a detention system provides an opportunity to screen and treat many at-risk youth.GOAL The goal of this study was to determine the cost-effectiveness of screening male youth for chlamydia on entry to detention. STUDY DESIGN: Incremental cost-effectiveness of 3 chlamydia screening strategies was compared for a hypothetical cohort of 4000 male youth per year: 1) universal chlamydia screening using a urine-based nucleic acid amplification test (NAAT), 2) selective NAAT screening of urine leukocyte esterase (LE)-positive urines, and 3) no screening. The model incorporated programmatic costs of screening and treatment and medical cost savings from sequelae prevented in infected males and female partners. The analysis was conducted from the healthcare system perspective. RESULTS: Chlamydia prevalence in the sampled population of 594 was 4.8%, and the average number of female sexual partners/infected male was 1.6. Universal NAAT screening was the most cost-effective strategy, preventing 37 more cases of pelvic inflammatory disease (PID) and 3 more cases of epididymitis than selective screening and saving an additional 24,000 dollars. The analysis was sensitive to NAAT cost, LE sensitivity, rate of PID development, PID sequelae cost, and number of female partners. Universal screening remained the most cost saving for prevalence as low as 2.8% or higher. CONCLUSIONS: Universal chlamydia screening of adolescent males on entry to detention was the most cost-effective strategy. Savings are primarily the result of the prevention of PID in recent and future partners of index males. Screening detained male youth using a urine-based NAAT provides a public health opportunity to significantly reduce chlamydia infections in youth at risk for sexually transmitted diseases.     

Pivampicillin compared with erythromycin for treating women with genital Chlamydia trachomatis infection.

In a randomised single blind study, pivampicillin was compared with erythromycin in women with urogenital Chlamydia trachomatis infections. The pivampicillin dosage was 700 mg twice a day and the erythromycin dosage 500 mg twice a day for seven days. Follow up took place on days 7 and 14 after the start of treatment. All 26 women treated with pivampicillin were culture negative for chlamydiae at the first and second follow up visits. All 23 women who received erythromycin were culture negative at the first follow up visit, but one was culture positive at the second follow up visit. Gastrointestinal side effects were recorded in five patients receiving pivampicillin and in nine receiving erythromycin. Two patients receiving erythromycin were withdrawn from treatment because of gastrointestinal disturbances, compared with none receiving pivampicillin.     

Diagnosis of rectal gonorrhoea by blind anorectal swabs compared with direct vision swabs taken via a proctoscope.

Eight hundred and twenty-three examinations were carried out on 662 homosexual patients. At each examination a blind anorectal swab and a rectal swab taken via a proctoscope were inoculated on to a culture plate. From a total of 100 gonococcal infections of the rectum 96 gave positive results from blind anorectal swabs and 99 from swabs taken via a proctoscope. Blind anorectal swabs proved to be a reliable method in the diagnosis of rectal gonorrhoea.     

Diagnosis of rectal gonorrhoea by blind anorectal swabs compared with direct vision swabs taken via a proctoscope.

Eight hundred and twenty-three examinations were carried out on 662 homosexual patients. At each examination a blind anorectal swab and a rectal swab taken via a proctoscope were inoculated on to a culture plate. From a total of 100 gonococcal infections of the rectum 96 gave positive results from blind anorectal swabs and 99 from swabs taken via a proctoscope. Blind anorectal swabs proved to be a reliable method in the diagnosis of rectal gonorrhoea.     

Introduction of Chlamydia trachomatis screening for young women in Germany

Screening for genital Chlamydia trachomatis infections for young sexually active women was incorporated into routine medical care of German statutory health insured patients starting in January 2008.The primary goal of this new preventive measure is the reduction of severe sequelae for women such as tubal infertility and ectopic pregnancies. The course of the deliberations leading to the Federal Joint Committee's decision is summarized in this review.     

A prediction rule for selective screening of Chlamydia trachomatis infection

BACKGROUND: Screening for Chlamydia trachomatis infections is aimed at the reduction of these infections and subsequent complications. Selective screening may increase the cost effectiveness of a screening programme. Few population based systematic screening programmes have been carried out and attempts to validate selective screening criteria have shown poor performance. This study describes the development of a prediction rule for estimating the risk of chlamydial infection as a basis for selective screening. METHODS: A population based chlamydia screening study was performed in the Netherlands by inviting 21,000 15-29 year old women and men in urban and rural areas for home based urine testing. Multivariable logistic regression was used to identify risk factors for chlamydial infection among 6303 sexually active participants, and the discriminative ability was measured by the area under the receiver operating characteristic curve (AUC). Internal validity was assessed with bootstrap resampling techniques. RESULTS: The prevalence of C trachomatis (CT) infection was 2.6% (95% CI 2.2 to 3.2) in women and 2.0% (95% CI 1.4 to 2.7) in men. Chlamydial infection was associated with high level of urbanisation, young age, Surinam/Antillian ethnicity, low/intermediate education, multiple lifetime partners, a new contact in the previous two months, no condom use at last sexual contact, and complaints of (post)coital bleeding in women and frequent urination in men. A prediction model with these risk factors showed adequate discriminative ability at internal validation (AUC 0.78). CONCLUSION: The prediction rule has the potential to guide individuals in their choice of participation when offered chlamydia screening and is a promising tool for selective CT screening at population level.     

Detection of Chlamydia trachomatis in genital swabs: comparison of commercial and in house amplification methods with culture

AIMS: To evaluate the sensitivity of the Roche Cobas, Roche Amplicor plate kit, ligase chain reaction (LCR), and an in house polymerase chain reaction (PCR) by titration of purified elementary bodies (EB) and also to test 245 urethral and endocervical specimens for Chlamydia trachomatis by the four assays as well as conventional culture. STUDY DESIGN: EB titrations were run in duplicate in each commercial assay and six times in the in house PCR. Clinical samples were aliquoted and tested by each assay and were considered positive if C trachomatis was detected by two or more separate tests or if the sample was either culture or immunofluorescence positive. Major outer membrane protein (MOMP) specific primers were used as a confirmatory assay for the in house PCR. RESULTS: The in house PCR, Roche Cobas Amplicor, LCR, and Amplicor plate kit gave detection limits of approximately 1, 1-2, 2, and 2-4 EBs respectively. By the criteria described above for definition of a C trachomatis positive result in clinical samples we identified 23 true positives among the 245 clinical specimens. The in house PCR detected all 23 giving a sensitivity of 100% and a specificity of 98%. The Roche Cobas Amplicor, Roche Amplicor plate kit, and LCR detected 21, 19, and 19 of these respectively giving sensitivities of 87.5%, 82%, and 82% respectively and specificities of 99.5%, 99%, and 100% respectively. The culture gave a sensitivity of 78% and specificity of 100%. CONCLUSION: All four amplification assays had a greater sensitivity than the culture used routinely in this laboratory. The in house plasmid PCR had the greatest sensitivity and when combined with confirmation by immunofluorescence detected the greatest number of positives. This increased sensitivity is likely to have been achieved by the use of a DNA purification step and of nested primers in the amplification stage and their combined use in routine diagnostic assays for chlamydia might increase the frequency of C trachomatis detections. However, this assay is much less user friendly than the two semiautomated commercial assays investigated in this study.