Pregnancies and Time to Pregnancy in Women With and Without a Previous Chlamydia trachomatis Infection.

BACKGROUND: A Chlamydia trachomatis infection (chlamydia) can result in tubal factor infertility in women. To assess if this association results in fewer pregnant women, we aimed to assess pregnancy incidences and time to pregnancy among women with a previous chlamydia infection compared with women without one and who were participating in the Netherlands Chlamydia Cohort Study (NECCST). METHODS: The NECCST is a cohort of women of reproductive age tested for chlamydia in a chlamydia screening trial between 2008 and 2011 and reinvited for NECCST in 2015 to 2016. Chlamydia status (positive/negative) was defined using chlamydia screening trial-nucleic acid amplification test results, chlamydia immunoglobulin G presence in serum, or self-reported chlamydia infections. Data on pregnancies were collected via questionnaires in 2015-2016 and 2017-2018. Overall pregnancies (i.e., planned and unplanned) and time to pregnancy (among women with a pregnancy intention) were compared between chlamydia-positive and chlamydia-negative women using Cox regressions. RESULTS: Of 5704 women enrolled, 1717 (30.1%; 95% confidence interval [CI], 28.9-31.3) women was chlamydia positive. Overall pregnancy proportions were similar in chlamydia-positive and chlamydia-negative women (49.0% [95% CI, 46.5-51.4] versus 50.5% [95% CI, 48.9-52.0]). Pregnancies per 1000 person-years were 53.2 (95% CI, 51.5-55.0) for chlamydia negatives and 83.0 (95% CI, 78.5-87.9) for chlamydia positives. Among women with a pregnancy intention, 12% of chlamydia-positive women had a time to pregnancy of >12 months compared with 8% of chlamydia negatives (P < 0.01). CONCLUSIONS: Overall pregnancy rates were not lower in chlamydia-positive women compared with chlamydia-negative women, but among women with a pregnancy intention, time to pregnancy was longer and pregnancy rates were lower in chlamydia-positive women. TRIAL REGISTRATION NUMBER: Dutch Trial Register NTR-5597.

Chlamydia trachomatis and the Risk of Pelvic Inflammatory Disease, Ectopic Pregnancy, and Female Infertility: A Retrospective Cohort Study Among Primary Care Patients.

BACKGROUND: We evaluated the risk of pelvic inflammatory disease (PID), ectopic pregnancy, and infertility in women with a previous Chlamydia trachomatis (CT) diagnosis compared with women who tested negative for CT and CT untested women, considering both targeted and incidental (ie, prescribed for another indication) use of CT-effective antibiotics. METHODS: This was a retrospective study of women aged 12-25 years at start of follow-up within the Clinical Practice Research Datalink GOLD database linked to index of multiple deprivation quintiles, 2000-2013. CT test status and antibiotic use were determined in a time-dependent manner. Risk of PID, ectopic pregnancy, or female infertility were evaluated using of Cox proportional hazard models. RESULTS: We studied 857 324 women, contributing 6 457 060 person-years. Compared with women who tested CT-negative, women who tested CT-positive had an increased risk of PID (adjusted hazard ratio [aHR], 2.36; 95% confidence interval [CI], 2.01-2.79), ectopic pregnancy (aHR, 1.87; 95% CI, 1.38-2.54), and infertility (aHR, 1.85; 95% CI, 1.27-2.68). The PID risk was higher for women with 2 or more positive CT tests than those with 1 positive test. PID risk increased with the number of previous antibiotic prescriptions, regardless of CT test status. CONCLUSIONS: We showed an association between CT-positive tests and 3 adverse reproductive health outcomes. Moreover, this risk increased with repeat CT infections. CT-effective antibiotic use showed no decreased risks of subsequent PID regardless of CT history. Our results confirm the reproductive health burden of CT, which requires adequate public health interventions.

Evaluation and enumeration of online test providers for sexually transmitted infections, specifically chlamydia, in the Netherlands.

OBJECTIVES: Online testing for STIs might complement regular care provided by general practitioners or STI clinics. Two types of online testing can be distinguished, self-testing and self-sampling (sending sample to a laboratory for diagnosis). Online testing can occur without consultation with a healthcare professional, therefore information given by providers is essential for informed decision-making. We aimed to enumerate online test providers in the Netherlands focusing on chlamydia tests, to evaluate information using quality indicators and to gain insight on the proportion of online testing in the STI testing arena. METHODS: We performed a systematic internet search to identify online STI test providers. Twenty quality indicators were evaluated on their websites; indicator scores were weighted by level of importance (expert opinion). High scoring providers were recommended, on the condition that the sensitivity and specificity of the test were above 95% and providers included a follow-up procedure in case of a positive result. Finally, providers were contacted to inquire about the number of sold tests, positivity rates and demographic characteristics of testers. RESULTS: Five out of 12 identified self-sample test providers could be recommended, versus zero out of eight self-test providers. Self-sample test providers gave complete and correct information on more indicators (67%) compared with self-test providers (38%). In 2015, an estimated 30 000-40 000 self-sample tests were purchased, and 12 000-25 000 self-tests, which is roughly 10%-15% of the total number of STI tests. CONCLUSION: This evaluation shows that some online self-sample test providers could be put forward as way of STI testing complementing regular testing options. None of the self-test providers were recommended. Regularly evaluating online test providers is advised to improve quality of the information on the websites. Finally, self-testing might not be suited for all populations as most information is provided in written format only.

National prevalence estimates of chlamydia and gonorrhoea in the Netherlands.

OBJECTIVES: National prevalence estimates of Chlamydia trachomatis (chlamydia) and Neisseria gonorrhoeae (gonorrhoea) are important for providing insights in the occurrence and control of these STIs. The aim was to obtain national prevalence estimates for chlamydia and gonorrhoea and to investigate risk factors associated with infection. METHODS: Between November 2016 and January 2017, we performed a national population-based cross-sectional probability sample survey among men and women aged 18-34 years in the Netherlands. Individuals were invited to complete a questionnaire about sexual health. At the end of the questionnaire, sexually active individuals could request a home-based sampling kit. Samples were tested for chlamydia and gonorrhoea using nucleic acid amplification test (NAAT). Logistic regression analyses were performed for predictors of participation and chlamydia infection. RESULTS: Of the 17 222 invited individuals, 4447 (26%) participated. Of these, 3255 were eligible for prevalence survey participation and 550 (17%) returned a sample. Participation in the prevalence survey was associated with age (20+) and risk factors for STI. We did not detect any gonorrhoea. The overall weighted prevalence of chlamydia was 2.8% (95% CI 1.5% to 5.2%); 1.1% (0.1% to 7.2%) in men and 5.6% (3.3% to 9.5%) in women. Risk factors for chlamydia infections in women aged 18-24 years were low/medium education level, not having a relationship with the person you had most recent sex with and age at first sex older than 16. CONCLUSIONS: Chlamydia and gonorrhoea prevalence were low in the general Dutch population, as was the participation rate. Repeated prevalence surveys are needed to analyse trends in STI prevalences and to evaluate control policies.

Relation between Chlamydia trachomatis infection and pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility in a Dutch cohort of women previously tested for chlamydia in a chlamydia screening trial.

OBJECTIVES: A better understanding of Chlamydia trachomatis infection (chlamydia)-related sequelae can provide a framework for effective chlamydia control strategies. The objective of this study was to estimate risks and risk factors of pelvic inflammatory disease (PID), ectopic pregnancy and tubal factor infertility (TFI) with a follow-up time of up until 8 years in women previously tested for chlamydia in the Chlamydia Screening Implementation study (CSI) and participating in the Netherlands Chlamydia Cohort Study (NECCST). METHODS: Women who participated in the CSI 2008-2011 (n=13 498) were invited in 2015-2016 for NECCST. Chlamydia positive was defined as a positive CSI-PCR test, positive chlamydia serology and/or self-reported infection (time dependent). Data on PID, ectopic pregnancy and TFI were collected by self-completed questionnaires. Incidence rates and HRs were compared between chlamydia-positive and chlamydia-negative women corrected for confounders. RESULTS: Of 5704 women included, 29.5% (95% CI 28.3 to 30.7) were chlamydia positive. The incidence rate of PID was 1.8 per 1000 person-years (py) (1.6 to 2.2) overall, 4.4 per 1000 py (3.3 to 5.7) among chlamydia positives compared with 1.4 per 1000 py (1.1 to 1.7) for chlamydia negatives. For TFI, this was 0.4 per 1000 py (0.3 to 0.5) overall, 1.3 per 1000 py (0.8 to 2.1) and 0.2 per 1000 py (0.1 to 0.4) among chlamydia positives and negatives, respectively. And for ectopic pregnancy, this was 0.6 per 1000 py (0.5 to 0.8) overall, 0.8 per 1000 py (0.4 to 1.5) and 0.6 per 1000 py (0.4 to 0.8) for chlamydia negatives. Among chlamydia-positive women, the strongest risk factor for PID was symptomatic versus asymptomatic infection (adjusted HR 2.88, 1.4 to 4.5) and for TFI age <20 versus >24 years at first infection (HR 4.35, 1.1 to 16.8). CONCLUSION: We found a considerably higher risk for PID and TFI in chlamydia-positive women, but the incidence for ectopic pregnancy was comparable between chlamydia-positive and chlamydia-negative women. Overall, the incidence rates of sequelae remained low. TRIAL REGISTRATION: NTR-5597.

STIs in sex partners notified for chlamydia exposure: implications for expedited partner therapy.

OBJECTIVES: Expedited partner therapy (EPT) may reduce chlamydia reinfection rates. However, the disadvantages of EPT for chlamydia include missing the opportunity to test for other STIs and unnecessary use of antibiotics among non-infected partners. As part of a larger study that investigated the feasibility of EPT in the Netherlands, we explored the frequency of STI among a potential EPT target population of chlamydia-notified heterosexual men and women attending STI clinics for testing. METHODS: Cross-sectional national STI/HIV surveillance data, which contain information on all consultations at STI clinics, were used to calculate STI positivity rates stratified by chlamydia notification and gender, and proportions of STI that were attributable to clients notified for chlamydia. RESULTS: Of all consultations in 2015 (n=101 710), 14 445 (14.4%) clients reported to be notified exclusively for chlamydia. Among chlamydia-notified clients, the chlamydia positivity rate was 34.2% (n=4947), and consequently 65.8% (n=9488) of them tested negative for chlamydia. Chlamydia-notified clients contributed to 10.2% of all gonorrhoea infections (n=174/1702) and 10.9% of all infectious syphilis, HIV and/or infectious hepatitis B infections (n=15/173). CONCLUSION: Implementing EPT without additional STI testing for all partners of chlamydia-infected index patients implies that STIs other than chlamydia will be missed. Although the chlamydia positivity rate was high among chlamydia-notified partners, two-thirds would unnecessarily use azithromycin. An evaluation of EPT against the current partner treatment strategy is needed to carefully weigh the potential health gains against the potential health losses and to explore the characteristics of EPT-eligible partners.

A pill for the partner via the chlamydia patient? Results from a mixed method study among sexual health care providers in the Netherlands.

BACKGROUND: Chlamydia prevalence in the Netherlands remains high despite targeted efforts. Effective Partner Notification (PN) and Partner Treatment (PT) can interrupt transmission and prevent re-infections. Patient Initiated Partner Treatment (PIPT) may strengthen chlamydia control. This study explores the current practice of PN and PT, and benefits of, and barriers and facilitators for PIPT among professionals in sexual health care in the Netherlands. METHODS: A qualitative study was performed among GPs, GP-assistants (GPAs), physicians and nurses working at Sexual Health Clinics (SHC) and key-informants on ethnical diversity using topic lists in focus groups (N = 40) and semi-structured questionnaires in individual interviews (N = 9). Topics included current practices regarding PN and PT, attitude regarding PIPT, and perceived barriers and facilitators for PIPT. Interviews were taped, transcribed verbatim, and coded using ATLAS.ti. A quantitative online questionnaire on the same topics was sent to all physicians and nurses employed at Dutch SHC (complete response rate 26% (84/321)). RESULTS: The qualitative study showed that all professionals support the need for more attention to PN, and that they saw advantages in PIPT. Mentioned barriers included unwilling PN-behaviour, Dutch legislation, several medical considerations and inadequate skills of GPs. Also, concerns about limited knowledge of cultural sensitivity around PN and PT were raised. Mentioned facilitators of PIPT were reliable home based test-kits, phone-contact between professionals and notified partners, more consultation time for GPs or GPAs and additional training. The online questionnaire showed that SHC employees agreed that partners should be treated as soon as possible, but also that they were reluctant towards PIPT without counselling and testing. CONCLUSIONS: Professionals saw advantages in PIPT, but they also identified barriers hampering the potential introduction of PIPT. Improving PN and counselling skills with specific focus on cultural sensitivity is needed. PIPT could be considered for specific partners. PIPT in combination with home based testing and using e-healthcare should be further explored and developed.

Partner notification and partner treatment for chlamydia: attitude and practice of general practitioners in the Netherlands; a landscape analysis.

BACKGROUND: Chlamydia prevalence remains high despite scaling-up control efforts. Transmission is not effectively interrupted without partner notification (PN) and (timely) partner treatment (PT). In the Netherlands, the follow-up of partners is not standardized and may depend on GPs' time and priorities. We investigated current practice and attitude of GPs towards PN and PT to determine the potential for Patient-Initiated Partner Treatment, which is legally not supported yet. METHODS: Multiple data-sources were combined for a landscape analysis. Quantitative data on (potential) PT were obtained from prescriptions in the national pharmacy register (2004-2014) and electronic patient data from NIVEL-Primary Care Database (PCD) and from STI consultations in a subgroup of sentinel practices therein. Furthermore, we collected information on current practice via two short questionnaires at a national GP conference and obtained insight into GPs' attitudes towards PN/PT in a vignette study among GPs partaking in NIVEL-PCD. RESULTS: Prescription data showed Azithromycin double dosages in 1-2% of cases in the pharmacy register (37.000 per year); probable chlamydia-specific repeated prescriptions or double dosages of other antibiotics in NIVEL-PCD (115/1078) could not be interpreted as PT for chlamydia with certainty. STI consultation data revealed direct PT in 6/100 cases, via partner prescription or double doses. In the questionnaires the large majority of GPs (>95% of 1411) reported to discuss PN of current and ex-partner(s) with chlamydia patients. Direct PT was indicated as most common method by 4% of 271 GPs overall and by 12% for partners registered in the same practice. Usually, GPs leave further steps to the patients (83%), advising patients to tell partners to get tested (56%) or treated (28%). In the vignette study, 16-20% of 268 GPs indicated willingness to provide direct PT, depending on patient/partner profile, more (24-45%) if patients would have the chance to notify their partner first. CONCLUSION: GPs in the Netherlands already treat some partners of chlamydia cases directly, especially partners registered in the same practice. Follow-up of partner notification and treatment in general practice needs more attention. GPs may be open to implement PIPT more often, provided there are clear guidelines to arrange this legally and practically.

Changes in chlamydia control activities in Europe between 2007 and 2012: a cross-national survey.

BACKGROUND: In 2012, the levels of chlamydia control activities including primary prevention, effective case management with partner management and surveillance were assessed in 2012 across countries in the European Union and European Economic Area (EU/EEA), on initiative of the European Centre for Disease Control (ECDC) survey, and the findings were compared with those from a similar survey in 2007. METHODS: Experts in the 30 EU/EEA countries were invited to respond to an online questionnaire; 28 countries responded, of which 25 participated in both the 2007 and 2012 surveys. Analyses focused on 13 indicators of chlamydia prevention and control activities; countries were assigned to one of five categories of chlamydia control. RESULTS: In 2012, more countries than in 2007 reported availability of national chlamydia case management guidelines (80% vs. 68%), opportunistic chlamydia testing (68% vs. 44%) and consistent use of nucleic acid amplification tests (64% vs. 36%). The number of countries reporting having a national sexually transmitted infection control strategy or a surveillance system for chlamydia did not change notably. In 2012, most countries (18/25, 72%) had implemented primary prevention activities and case management guidelines addressing partner management, compared with 44% (11/25) of countries in 2007. CONCLUSION: Overall, chlamydia control activities in EU/EEA countries strengthened between 2007 and 2012. Several countries still need to develop essential chlamydia control activities, whereas others may strengthen implementation and monitoring of existing activities.

The need to scale up HIV indicator condition-guided testing for early case-finding: a case-control study in primary care.

BACKGROUND: European guidelines recommend offering an HIV test to individuals who display HIV indicator conditions (ICs). We aimed to investigate the incidence of ICs in primary care reported in medical records prior to HIV diagnosis. METHODS: We did a cross-sectional search in an electronic general practice database using a matched case-control design to identify which predefined ICs registered by Dutch GPs were most associated with an HIV-positive status prior to the time of diagnosis. RESULTS: We included 224 HIV cases diagnosed from 2009 to 2013, which were matched with 2,193 controls. Almost two thirds (n = 136, 60.7%) of cases were diagnosed with one or more ICs in the period up to five years prior to the index date compared to 18.7% (n = 411) of controls. Cases were more likely to have an IC than controls: in the one year prior to the index date, the odds ratio (OR) for at least one condition was 11.7 (95% CI: 8.3 to 16.4). No significant differences were seen in the strength of the association between HIV diagnosis and ICs when comparing genders, age groups or urbanisation levels. There is no indication that subgroups require a different testing strategy. CONCLUSIONS: Our study shows that there are opportunities for IC-guided testing in primary care. We recommend that IC-guided testing be more integrated in GPs' future guidelines and that education strategies be used to facilitate its implementation in daily practice.

Urogenital Chlamydia trachomatis strain types, defined by high-resolution multilocus sequence typing, in relation to ethnicity and urogenital symptoms among a young screening population in Amsterdam, The Netherlands.

INTRODUCTION: Previous studies found conflicting results regarding associations between urogenital Chlamydia trachomatis infections and ethnicity or urogenital symptoms among at-risk populations using either ompA-based genotyping or high-resolution multilocus sequence typing (MLST). This study applied high-resolution MLST on samples of individuals from a selected young urban screening population to assess the relationship of C. trachomatis strain types with ethnicity and self-reported urogenital symptoms. Demographic and sexual risk behaviour characteristics of the identified clusters were also analysed. METHODS: We selected C. trachomatis-positive samples from the Dutch Chlamydia Screening Implementation study among young individuals in Amsterdam, the Netherlands. All samples were typed using high-resolution MLST. Clusters were assigned using minimum spanning tree analysis and were combined with epidemiological data of the participants. RESULTS: We obtained full MLST data for C. trachomatis-positive samples from 439 participants and detected nine ompA genovars. MLST analysis identified 175 sequence types and six large clusters; in one cluster, participants with Surinamese/Antillean ethnicity were over-represented (58.8%) and this cluster predominantly consisted of genovar I. In addition, we found one cluster with an over-representation of participants with Dutch ethnicity (90.0%) and which solely consisted of genovar G. No association was observed between C. trachomatis clusters and urogenital symptoms. CONCLUSIONS: We found an association between urogenital C. trachomatis clusters and ethnicity among young screening participants in Amsterdam, the Netherlands. However, no association was found between C. trachomatis clusters and self-reported urogenital symptoms.

Chlamydia screening is not cost-effective at low participation rates: evidence from a repeated register-based implementation study in The Netherlands.

OBJECTIVE: In three pilot regions of The Netherlands, all 16-29 year olds were invited to participate in three annual rounds of Chlamydia screening. The aim of the present study is to evaluate the cost-effectiveness of repeated Chlamydia screening, based on empirical data. METHODS: A mathematical model was employed to estimate the influence of repeated screening on prevalence and incidence of Chlamydial infection. A model simulating the natural history of Chlamydia was combined with cost and utility data to estimate the number of major outcomes and quality-adjusted life-years (QALYs) associated with Chlamydia. Six screening scenarios (16-29 years annually; 16-24 years annually; women only; biennial screening; biennial screening women only; screening every five years) were compared with no screening in two sexual networks, representing both lower ('national network') and higher ('urban network') baseline prevalence. Incremental cost-effectiveness ratios (ICERs) for the different screening scenarios were estimated. Uncertainty and sensitivity analyses were performed. RESULTS: In all scenarios and networks, cost per major outcome averted are above €5000. Cost per QALY are at least €50,000. The default scenario as piloted in the Netherlands was least cost-effective, with ICERs of €232,000 in the national and €145,000 in the urban sexual network. Results were robust in sensitivity analyses. CONCLUSIONS: It is unlikely that repeated rounds of Chlamydia screening will be cost-effective. Only at high levels of willingness to pay for a QALY (>€50,000) screening may be more cost-effective than no screening.

Comparison of STI-related consultations among ethnic groups in the Netherlands: an epidemiologic study using electronic records from general practices.

BACKGROUND: Currently, surveillance of sexually transmitted infections (STIs) among ethnic minorities (EM) in the Netherlands is mainly performed using data from STI centers, while the general practitioner (GP) is the most important STI care provider. We determined the frequency of STI-related episodes at the general practice among EM, and compared this with the native Dutch population. METHODS: Electronic medical records from 15-to 60-year-old patients registered in a general practice network from 2002 to 2011 were linked to the population registry, to obtain (parental) country of birth. Using diagnoses and prescription codes, we investigated the number of STI-related episodes per 100,000 patient years by ethnicity. Logistic regression analyses (crude and adjusted for gender, age, and degree of urbanization) were performed for 2011 to investigate differences between EM and native Dutch. RESULTS: The reporting rate of STI-related episodes increased from 2004 to 2011 among all ethnic groups, and was higher among EM than among native Dutch, except for Turkish EM. After adjustment for gender, age, and degree of urbanization, the reporting rate in 2011 was higher among Surinamese [Odds Ratio (OR) 1.99, 95 % confidence interval (CI) 1.70-2.33], Antillean/Aruban (OR 2.48, 95 % CI 2.04-3.01), and Western EM (OR 1.24, 95 % CI 1.11-1.39) compared with native Dutch, whereas it was lower among Turkish EM (OR 0.48, 95 % CI 0.37-0.61). Women consulted the GP relatively more frequently regarding STIs than men, except for Turkish and Moroccan women. CONCLUSIONS: Most EM consult their GP more often for STI care than native Dutch. However, it remains unclear whether this covers the need of EM groups at higher STI risk. As a first point of contact for care, GPs can play an important role in reaching EM for (proactive) STI/HIV testing.

Use of Chlamydia trachomatis high-resolution typing: an extended case study to distinguish recurrent or persistent infection from new infection.

OBJECTIVES: Repeated infections of Chlamydia trachomatis may be new infections or persistent infections due to treatment failure or due to unresolved infections in sexual partners. We aimed to establish the value of using high-resolution multilocus sequence typing (CT-MLST) to discriminate repeated C trachomatis infections. METHODS: Paired C trachomatis positive samples (baseline (T0) and after 6 months (T1)) were selected from two Dutch screening implementation studies among young heterosexual people. Typing with six CT-MLST loci included the ompA gene. The uniqueness of strains was assessed using 256 reference CT-MLST profiles. RESULTS: In 27 out of 34 paired cases, full sequence types were obtained. A multilocus (13 cases) or single locus variant (4 cases) was seen, indicating 17 new C trachomatis infections at T1. The ompA genovar was identical for 5 of 17 discordant cases. The 10 cases with concordant typing results were categorised as treatment failure (5 cases) versus persistent or recurrent infections (5 cases). Surprisingly, these concordant cases had C trachomatis strains that were either unique or found in small clusters. The median time between T0 and T1 did not differ between the concordant and discordant cases. CONCLUSIONS: High-resolution typing was superior in discriminating new infections compared with only using ompA genovar typing. Many cases (37%) showed exactly the same C trachomatis strain after 6 months. CT-MLST is not conclusive in distinguishing recurrent infections from treatment failure.

High yield of reinfections by home-based automatic rescreening of Chlamydia positives in a large-scale register-based screening programme and determinants of repeat infections.

INTRODUCTION: In a systematic internet-based Chlamydia Screening Implementation Programme in The Netherlands, all chlamydia-positive participants automatically received a testkit after 6 months to facilitate early detection of repeat infections. The authors describe participation in repeat testing and prevalence and determinants of repeat infection during three consecutive annual screening rounds. METHODS: Data collection included information on testkits sent, samples received and results of laboratory tests at time of baseline test and retest; (sexual) behavioural variables and socio-demographic variables were assessed. Chlamydia positives were requested to answer additional questions about treatment and partner notification 10 days after checking their results. RESULTS: Retest rate was 66.3% (2777/4191). Retest chlamydia positivity was 8.8% (242/2756) compared with a chlamydia positivity at first screening test of 4.1%. Chlamydia positivity was significantly higher in younger age groups (14.6% in 16-19 years, 8.5% and 5.5% in 20-24 and 25-29 years; p<0.01); in participants with lower education (15.2% low, 11.1% medium and 5.1% high; p<0.001) and in Surinamese/Antillean (13.1%), Turkish/Moroccan (12.9%) and Sub-Saharan African participants (18.6%; p<0.01). At baseline, 88.7% infected participants had reportedly been treated and treatment of current partner was 80.1%. DISCUSSION: Automated retesting by sending a testkit after 6 months to all chlamydia positives achieved high retest uptake and yielded a positivity rate twice as at baseline and can therefore be recommended as an additional strategy for chlamydia control. The high rate of repeat infections among known risk groups suggests room for improvement in patient case management and in effective risk reduction counselling.

Retesting for genital Chlamydia trachomatis among visitors of a sexually transmitted infections clinic: randomized intervention trial of home- versus clinic-based recall.

BACKGROUND: Reinfections of Chlamydia trachomatis (Ct) are common. In a two-armed intervention study at an urban STI clinic in the Netherlands, heterosexual Ct-positive visitors received an invitation for retesting after 4-5 months. Interventions were either home-based sampling by mailed test-kit, or clinic-based testing without appointment. METHODS: Data collection included socio-demographic and sexual behavioural variables at first (T0) and repeat test (T1). Participation in retesting, prevalence and determinants of repeat infection among study participants are described and compared with findings from non-participants. RESULTS: Of the 216 visitors enrolled in the study, 75 accepted retesting (35%). The retest participation was 46% (50/109) in the home group versus 23% (25/107) in the clinic group (p = 0.001). Men were less often retested than women (15% versus 43%, p < 0.001). The overall chlamydia positivity rate at retest was 17.3% (13/75) compared to 12.4% seen at all visits at the STI clinic in 2011. Repeated infections were more frequent among non-Dutch than Dutch participants (27.0% versus 7.9%; p = 0.04) and in persons reporting symptoms (31.0% versus 7.0%; p = 0.01). Both untreated infections of current partners as well as unprotected sex with new partners contribute to repeated infections. CONCLUSION: The high rate of repeated infections indicates the need for interventions to increase retesting; improvement of partner-management and risk reduction counselling remain necessary. Home- based testing was more effective than clinic-based testing. However other strategies, including self-triage of patients, may also increase repeat testing rates and personal preferences should be taken into account.

Systematic selection of screening participants by risk score in a Chlamydia screening programme is feasible and effective.

OBJECTIVES: Systematic screening for Chlamydia trachomatis by individual invitation can be optimised by filtering participants on risk profile, excluding people at no or low risk. The authors investigated this technique in a large-scale chlamydia screening programme in The Netherlands in one rural region where relatively low prevalence was expected (<2%). METHODS: Invitees were alerted by personal letter to log in to http://www.chlamydiatest.nl and fill in an 8-item questionnaire. Only invitees with sufficient score could proceed to request a test kit. The authors investigated the effect of selection on participation, positivity and acceptability in three screening rounds and on the number needed to invite and the number needed to screen. RESULTS: The selection led to exclusion of 36% of potential participants and a positivity rate of 4.8% among participants, achieving similar number needed to screen values in the rural and urban areas. Higher scores were clearly related to higher positivity rates. Persons who were excluded from participation did not have a lower response in the next round. The acceptability study revealed disappointment about exclusion of 30% of excluded participants but most approved of the screening set-up. CONCLUSIONS: Systematic selection of screening participants by risk score is feasible and successful in realising higher positivity rates. A somewhat stricter selection could be applied in the rural and urban areas of the screening programme. Multiple-item selection with a cut-off total score may work better than, more commonly used, selection by single criteria, especially in low-risk populations. Acceptability of selection is high but could still be improved by better communication on expectations.

Who participates in the Dutch Chlamydia screening? A study on demographic and behavioral correlates of participation and positivity.

BACKGROUND: In the Netherlands, an Internet-based Chlamydia Screening Implementation was initiated in 3 regions, aiming to reduce population prevalence by annual testing and treatment of people aged 16 to 29 years. We studied who was reached in the first screening round by relating participation and chlamydia positivity to sociodemographic and sexual risk factors. METHODS: Data from the 2008/2009 screening round were analyzed (261,025 screening invitations, 41,638 participants). Participation rates were adjusted for the sexually active population. Sociodemographic and behavioral correlates of screening participation and positivity were studied by (multilevel) logistic regression models. RESULTS: The overall adjusted participation rate in the first screening round was 19.5% (95% confidence interval, 19.4-19.7) among sexually active people (women, 25%; men, 13%). Sociodemographic factors associated with lower participation were male gender (odds ratio [OR], male 1 vs. female 1.8), young age (OR, 16-19 1 vs. older groups 1.7-2.1), non-Dutch origin (OR between 0.7-0.9), lower education (OR, low 1 vs. high 1.4), high community risk level (0.8), and low socioeconomic status (0.9). Behavioral factors associated with lower participation were a long-standing relationship (0.7) and no reported history or symptoms of sexually transmitted infections (no symptoms, 0.4-0.6) . Factors most strongly related to higher Ct positivity were young age (OR, 1 vs. older groups 0.5-0.8), non-Dutch origin (1.4-2.8), non-Dutch steady partner (1.9-2.7), residence in a high-risk area (1.4-1.5), lower education (high, 0.3-0.5), and a history or symptoms of sexually transmitted infection (no symptoms, 0.4-0.6). CONCLUSIONS: Sociodemographic factors associated with lower participation were also associated with higher Ct positivity, showing that high-risk demographic groups are more difficult to mobilize than low-risk groups. Independent of this, higher behavioral risk levels were associated with higher participation rates, suggesting self-selection for screening based on the persons' risk (perception) in both low- and high community risk groups. Our study shows the complexity of the process, including individual and community factors that also interact, when screening for chlamydia.

Keeping participants on board: increasing uptake by automated respondent reminders in an Internet-based chlamydia screening in the Netherlands.

BACKGROUND: Effectiveness of Chlamydia screening programs is determined by an adequate level of participation and the capturing of high-risk groups. This study aimed to evaluate the contribution of automated reminders by letter, email and short message service (SMS) on package request and sample return in an Internet-based Chlamydia screening among people aged 16 to 29 years in the Netherlands. METHODS: Individuals not responding to the invitation letter received a reminder letter after 1 month. Email- and SMS-reminders were sent to persons who did not return their sample. It was examined to what extent reminders enhanced the response rate (% of package requests) and participation rate (% of sample return). Sociodemographic and behavioural correlates of providing a cell phone number and participation after the reminder(s) were studied by logistic regression models. RESULTS: Of all respondents (screening round 1: 52,628, round 2: 41,729), 99% provided an email address and 72% a cell phone number. Forty-two percent of all package requests were made after the reminder letter. The proportion of invitees returning a sample increased significantly from 10% to 14% after email/SMS reminders (round 2: from 7% to 10%). Determinants of providing a cell-phone number were younger age (OR in 25-29 year olds versus 16-19 year olds = 0.8, 95%CI 0.8-0.9), non-Dutch (OR in Surinam/Antillean versus Dutch = 1.3, 95%CI 1.2-1.4, Turkish/Moroccan: 1.1, 95%CI 1.0-1.2, Sub Sahara African: 1.5, 95%CI 1.3-1.8, non-Western other 1.1, 95%CI 1.1-1.2), lower educational level (OR in high educational level versus low level = 0.8, 95%CI 0.7-0.9), no condom use during the last contact with a casual partner (OR no condom use versus condom use 1.2, 95%CI 1.1-1.3), younger age at first sexual contact (OR 19 years or older versus younger than 16: 0.7, 95%CI 0.6-0.8). Determinants for requesting a test-package after the reminder letter were male gender (OR female versus male 0.9 95%CI 0.8-0.9), non-Dutch (OR in Surinam/Antillean versus Dutch 1.3, 95%CI 1.2-1.4, Turkish/Moroccan: 1.4, 95%CI 1.3-1.5, Sub Sahara African: 1.4, 95%CI 1.2-1.5, non-Western other: 1.2, 95%CI 1.1-1.2), having a long-term steady partnership (long-term versus short-term.1.2 95%CI 1.1-1.3). Email/SMS reminders seem to have resulted in more men and people aged 25-29 years returning a sample. CONCLUSIONS: Nearly all respondents (99.5%) were reachable by modern communication media. Response and participation rates increased significantly after the reminders. The reminder letters also seemed to result in reaching more people at risk. Incorporation of automated reminders in Internet-based (Chlamydia) screening programs is strongly recommended.