A prediction rule for selective screening of Chlamydia trachomatis infection

Derivation and Internal Validation of a Risk Score for Predicting Chlamydia trachomatis Infection in Kenyan Women Planning Conception

BACKGROUND

Availability of laboratory confirmation of sexually transmitted infections is increasing in low- and middle-income countries, but costs continue to limit their access. Chlamydia trachomatis (CT) is a sexually transmitted infection of significant clinical importance, particularly among women. This study aimed to develop a risk score to identify women with a higher likelihood of CT infection, who could then be prioritized for laboratory testing, in a population of Kenyan women planning pregnancies.

METHODS

Women with fertility intentions were included in this cross-sectional analysis. Logistic regression was used to estimate odds ratios for the association between demographic, medical, reproductive, and behavioral characteristics and the prevalence of CT infection. A risk score was developed and validated internally based on the regression coefficients in the final multivariable model.

RESULTS

The prevalence of CT was 7.4% (51 of 691). A risk score for predicting CT infection, with scores 0 to 6, was derived from participants' age, alcohol use, and presence of bacterial vaginosis. The prediction model yielded an area under the receiver operating curve of 0.78 (95% confidene interval [Cl], 0.72-0.84). A cutoff of ≤2 versus >2 identified 31.8% of women as higher risk with moderate sensitivity (70.6%; 95% Cl, 56.2-71.3) and specificity (71.3%; 95% Cl, 67.7-74.5). The bootstrap-corrected area under the receiver operating curve was 0.77 (95% Cl, 0.72-0.83).

CONCLUSIONS

In similar populations of women planning pregnancies, this type of risk score could be useful for prioritizing women for laboratory testing and would capture most women with CT infections while performing more costly testing in less than half of the population.

Area-based comparison of risk factors and testing rates to improve sexual health care access: cross-sectional population-based study in a Dutch multicultural area

OBJECTIVES

Areas with high sexually transmitted infection (STI) testing rates may not require additional strategies to improve testing. However, it may be necessary to intervene in areas with elevated STI risk, but with low STI testing rates. We aimed to compare STI-related risk profiles and STI testing rates by geographical area to determine areas for improvement of sexual healthcare access.

DESIGN

Cross-sectional population-based study.

SETTING

Greater Rotterdam area, the Netherlands (2015-2019).

PARTICIPANTS

All residents aged 15-45 years. Individual population-based register data were matched with laboratory-based STI testing data of general practitioners (GPs) and the only sexual health centre (SHC).

OUTCOME MEASURES

Postal code (PC) area-specific STI risk scores (based on age, migratory background, education level and urbanisation), STI testing rates and STI positivity.

RESULTS

The study area consists of approximately 500 000 residents aged 15-45 years. Strong spatial variation in STI testing, STI positivity and STI risk was observed. PC area testing rate ranged from 5.2 to 114.9 tests per 1000 residents. Three PC clusters were identified based on STI risk and testing rate: (1) high-high; (2) high-low; (3) low, independently of testing rate. Clusters 1 and 2 had comparable STI-related risk and STI positivity, but the testing rate differed greatly (75.8 vs 33.2 per 1000 residents). Multivariable logistic regression analysis with generalised estimating equation was used to compare residents in cluster 1 and cluster 2. Compared with cluster 1, residents in cluster 2 more often did not have a migratory background, lived in less urbanised areas with higher median household income, and more distant from both GP and SHC.

CONCLUSION

The determinants associated with individuals living in areas with high STI-related risk scores and low testing rates provide leads for improvement of sexual healthcare access. Opportunities for further exploration include GP education, community-based testing and service (re)allocation.

Investigation and management of abnormal uterine bleeding in reproductive-aged women: a descriptive review of national and international recommendations

PURPOSE

To review and compare the most recently published recommendations on the investigation and management of abnormal uterine bleeding (AUB).

MATERIALS AND METHODS

A descriptive review of recommendations from the American College of Obstetricians and Gynaecologists (ACOG), the National Institute for Health and Care Excellence (NICE), the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG), the Society of Obstetricians and Gynaecologists of Canada (SOGC) and the International Federation of Gynaecology and Obstetrics (FIGO) on AUB in reproductive-aged women was carried out.

RESULTS

There is a consensus that detailed personal and family history along with physical examination are essential in the investigation of menstrual, intermenstrual or postcoital AUB. All the medical societies recommend transvaginal ultrasound as the first-line imaging modality to determine the AUB cause. Moreover, they agree (except for RANZCOG) that, in women with AUB, endometrial biopsy should only be performed if additional risk factors for endometrial cancer are present. Laboratory tests may be helpful in the AUB investigation; however, there are several discrepancies among the recommendations. Regarding AUB management, NICE, ACOG and SOGC agree that the administration of hormonal or non-hormonal medications should be the first-line treatment modality in bleeding disorders and absent or minor structural pelvic pathology. Surgical management should be preferred in cases of identified polyps, large fibroids or unsuccessful pharmacological treatment.

CONCLUSIONS

Since AUB affects a significant proportion of reproductive-aged women, the main objective is to improve the quality of life of these patients without missing cases of malignancy.

Feasibility of anorectal chlamydia testing in women: a cross-sectional survey among general practitioners

BACKGROUND

Anorectal Chlamydia trachomatis (CT) may be clinically relevant for women in general practice. Although anorectal CT testing in this setting may prevent underdiagnosis and undertreatment, its feasibility is questioned as GPs currently rarely order anorectal CT tests, for yet unknown reasons.

OBJECTIVE

To explore the feasibility of anorectal CT testing in women in general practice.

METHODS

GPs across the Netherlands were invited directly (n = 1481) and by snowball sampling (n = 330) to join an online cross-sectional survey that asked about the acceptability of and barriers for (standard) anorectal testing in women during CT-related consultations. Data were analysed with univariable and multivariable logistic regression models.

RESULTS

The questionnaire was opened by 514 respondents (28%, 514/1811) and 394 fully completed it. GPs' acceptability of anorectal testing by either self-sampling or provider-sampling was high (86%). Twenty-eight percent of GPs felt neutral, and 43% felt accepting towards standard anorectal testing. Nevertheless, 40% of GPs had never tested for anorectal CT in women, which was associated with a reported difficulty in asking about anal sex (odds ratio [OR]: 3.07, 95% confidence interval [CI]: 1.21-7.80), infrequency of anal sexual history taking (OR: 11.50, 95% CI: 6.39-20.72), low frequency of urogenital CT testing (OR 3.44, 95%-CI: 1.86-6.38) and with practicing in a non-urban area (OR: 2.27, 95% CI: 1.48-3.48). Acceptability of anorectal testing was not associated with the studied factors.

CONCLUSION

This quantitative survey shows that anorectal CT testing is feasible based on its acceptability, but is likely hindered by a lower awareness of (anorectal) CT in GPs.

Educational level and risk of sexually transmitted infections among clients of Dutch sexual health centres

This study aimed to assess whether educational level is an independent determinant for sexually transmitted infections (STIs) among clients consulting Dutch sexual health centres (SHCs). With data from the National STI surveillance database (2015-2017), generalized estimating equations corrected for (sexual) risk factors were used to estimate associations between educational level and chlamydia and gonorrhoea among women (n = 146,020), heterosexual men (n = 82,882) and men who have sex with men (MSM) (n = 52,149) and syphilis and HIV among MSM. Compared to the highest educational level (bachelor/master), all lower educational levels were associated with gonorrhoea among women (adjusted odds ratio 1.40; 95% CI 1.18-1.66 for higher general/pre-university level to 3.57; 95% CI 2.66-4.81 for no education/elementary school level) and heterosexual men (respectively 1.36; 1.06-1.74 to 3.84; 2.89-5.09). Women with no education/elementary school level (1.37; 1.17-1.62) and heterosexual clients with (pre-)vocational secondary educational level were more likely to test positive for chlamydia (women: 1.43; 1.39-1.48 and heterosexual men: 1.31; 1.26-1.37) than clients with higher general/pre-university level or bachelor/master level. In MSM, (pre-)vocational secondary educational level was associated with chlamydia (1.16; 1.11-1.22), gonorrhoea (1.15; 1.10-1.21) and syphilis (1.18; 1.08-1.29), and both (pre-)vocational secondary educational level (1.48; 1.25-1.76) and no education/elementary school level (1.81; 1.09-3.00) were associated with HIV. Lower educational levels were independent determinants of STI in SHC clients. Sexual health centres could facilitate STI testing and care among lower educated people by prioritizing their access.

Recurrent post-coital bleeding: Should colposcopy still be mandatory?

BACKGROUND

Colposcopy has been recommended for all women with recurrent post-coital bleeding (PCB) even if their cervical cytology or co-test (involving oncogenic human papillomavirus (HPV) DNA testing and cytology) are negative.

AIMS

To determine the risk of cervical cancer and its precursors among women with recurrent PCB with negative cytology or co-test.

MATERIALS AND METHODS

A retrospective analysis of two cohorts of women with PCB referred to a tertiary colposcopy clinic. Cohort (1) (n = 1846) between 1 January 2000 and 31 December 2016 (cytology-based screening) and Cohort (2) (n = 215) from 1 January 2018 to 31 December 2019 after introduction of primary HPV screening.

RESULTS

In 1217 (65.9%) women in Cohort (1) referred with negative cytology, there was one cancer (0.08%) and 22 high-grade squamous intraepithelial lesions (HSIL (cervical intraepithelial neoplasia 2/3)) on histopathology. In Cohort (2), there was no cancer or HSIL in 83 women with negative co-tests (negative for oncogenic HPV and cytology). False-negative cytology after a negative referral cytology or co-test was low with 2% of repeat cytology at initial colposcopy showing possible HSIL or worse.

CONCLUSIONS

Women presenting with PCB and negative cytology alone have a low risk of cancer and could have HPV testing before being triaged to colposcopy. We showed that with the assurance of a negative co-test and the low likelihood of false-negative cytology, these women could avoid colposcopy unless cervical cancer is clinically suspected. There is a need for a larger cohort study to substantiate our findings with more precision.

Detection of chlamydia trachomatis infection among the pregnant women attending a tertiary care hospital in Kerala - South India by polymerase chain reaction

Background

Chlamydia trachomatis infection is the most prevalent bacterial sexually transmitted infection and may influence pregnancy outcome.

Aims and Objectives

This study was conducted to assess Chlamydial infection during pregnancy by PCR.

Materials and Methods

Study group consists of patients who are attending the antenatal clinics. Endocervical swabs were collected from 300 patients.

Results

Off the 300 samples tested, 29 were positive as per PCR which used CT F : 5' CGT GTC GGC AAT CCT GCT GAT 3' and CT R : 5' GTC GAT AAC ATA GTC ACG ATA GTC 3'as the primers.

Conclusion

This suggests there is a prevalence of Chlamydia trachomatis in our population which is 10%. Hence, it should be noted as a significant public health problem especially among sexually active young women of child bearing age. Timely detection and prompt treatment of Chlamydial infection during pregnancy can eliminate its adverse outcomes.

Evaluation of the prevalence of sexually transmitted bacterial pathogens in Northern Cyprus by nucleic acid amplification tests, and investigation of the relationship between these pathogens and cervicitis

Objective:

To evaluate the prevalence of pathogens, Chlamydia trachomatis, Neisseria gonorrhea and Trichomonas vaginalis, Mycoplasma hominis, Mycoplasma genitalium, Ureaplasma urealyticum, and Ureaplasma parvum in women via multiplex-polymerase chain reaction (PCR)-deoxyribonucleic acid (DNA).

Materials and Methods:

Cervical swabs of 273 women in reproductive age who underwent gynecologic examination in our outpatient clinic were evaluated using the multiplex-PCR-DNA method. The presence of cervicitis, contraceptive methods, marital status, and the number of partners were evaluated.

Results:

One hundred six (39%) of the 273 women had at least one bacterium, 25 women (9.8%) had two bacteria, and three women (1%) had three bacteria. U. urealyticum was the most frequently encountered bacterium (13.9%), followed by M. hominis (12.8%), U. parvum (12.4%), C. trachomatis (5.4%), M. genitalium (2.9%), N. gonorrhea (2.5%), and T. vaginalis (0.3%). Bacterial infection was detected more frequently in women aged <25 years, single, who had multiple partners, and clinically diagnosed with cervicitis. The cervicitis rate was 39% in our study. M. genitalium was significantly more frequent in women with cervicitis than in women without cervicitis (5.6 vs. 1.2%, p=0.005). C. trachomatis and N. gonorrhea, which are often associated with cervicitis, were comparable in women with and without cervicitis.

Conclusion:

Women with clinically diagnosed cervicitis or even with a normal-appearing cervix should be tested using multiplex-real-time PCR-nucleic-acidamplification tests on suspicion of such an infection. M. genitalium is an emerging bacterial agent for cervicitis along with C. trachomatis and N. gonorrhea.

Regional differences in chlamydia and gonorrhoeae positivity rate among heterosexual STI clinic visitors in the Netherlands: contribution of client and regional characteristics as assessed by cross-sectional surveillance data

OBJECTIVES

To assess to what extent triage criteria, client and regional characteristics explain regional differences in Chlamydia trachomatis (Ct) and Neisseria gonorrhoeae (Ng) positivity in sexually transmitted infection (STI) clinics.

DESIGN

Retrospective cross-sectional study on the Dutch STI surveillance database of all 24 STI clinics.

PARTICIPANTS

STI clinic visits of heterosexual persons in 2015 with a Ct (n=101 495) and/or Ng test (n=101 081).

PRIMARY OUTCOME MEASURE

Ct and Ng positivity and 95% CI was assessed for each STI clinic. Two-level logistic regression analyses were performed to calculate the percentage change in regional variance (PCV) after adding triage criteria (model 1), other client characteristics (model 2) and regional characteristics (model 3) to the empty model. The contribution of single characteristics was determined after removing them from model 3.

RESULTS

Ct positivity was 14.9% and ranged from 12.6% to 20.0% regionally. Ng positivity was 1.7% and ranged from 0.8% to 3.8% regionally. For Ct, the PCV was 11.7% in model 1, 32.2% in model 2% and 59.3% in model 3. Age, notified for Ct (triage), level of education (other characteristics) and regional degree of urbanisation (region) explained variance most. For Ng, the PCV was 38.7% in model 1, 61.2% in model 2% and 69.1% in model 3. Ethnicity (triage), partner in risk group, level of education and neighbourhood (other characteristics) and regional socioeconomic status (SES) explained variance most. A significant part of regional variance remained unexplained.

CONCLUSIONS

Regional variance was explained by differences in client characteristics, indicating that triage and self-selection influence positivity rates in the surveillance data.Clustering of Ng in low SES regions additionally explained regional variance in Ng; targeted interventions in low SES regions may assist Ng control. Including educational level as triage criterion is recommended. Studies incorporating prevalence data are needed to assess whether regional clustering underlies unexplained regional variance.

Differences in Chlamydia trachomatis seroprevalence between ethnic groups cannot be fully explained by socioeconomic status, sexual healthcare seeking behavior or sexual risk behavior: a cross-sectional analysis in the HEalthy LIfe in an Urban Setting (HELIUS) study

Background

In the Netherlands, there are strong disparities in Chlamydia trachomatis (CT) prevalence between ethnic groups. The current study aims to identify whether socioeconomic status, sexual risk behavior and sexual healthcare seeking behavior may explain differences in CT seroprevalence between ethnic groups.

Methods

We used 2011–2014 baseline data of the HELIUS (HEalthy LIfe in an Urban Setting) study, a multi-ethnic population-based cohort study in Amsterdam, the Netherlands, including participants from Dutch, African Surinamese, South-Asian Surinamese, Ghanaian, Moroccan and Turkish origin. For this analysis, we selected sexually active, heterosexual participants aged 18–34 years old. CT seroprevalence was determined using a multiplex serology assay. The CT seroprevalence ratios between different ethnicities are calculated and adjusted for potential indicators of socioeconomic status, sexual risk behavior and sexual healthcare seeking behavior.

Results

The study population consisted of 2001 individuals (52.8% female) with a median age of 28 years (IQR 24–31). CT seropositivity differed by ethnicities and ranged from 71.6% (African Surinamese), and 67.9% (Ghanaian) to 31.1% (Turkish). The CT seroprevalence ratio of African Surinamese was 1.72 (95% CI 1.43–2.06) and 1.52 (95% CI 1.16–1.99) of Ghanaian as compared to the Dutch reference group, after adjustment for socioeconomic status, sexual risk behavior and sexual healthcare seeking behavior.

Conclusions

Indicators of socioeconomic status, sexual risk behavior, and sexual health seeking behavior could not explain the higher CT seroprevalence among African Surinamese and Ghanaian residents of Amsterdam.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3533-7) contains supplementary material, which is available to authorized users.

Deriving a clinical prediction rule to target sexual healthcare to women attending British General Practices

Some women attending General Practices (GPs) are at higher risk of unintended pregnancy (RUIP) and sexually transmitted infections (STI) than others. A clinical prediction rule (CPR) may help target resources using psychosocial questions as an acceptable, effective means of assessment. The aim was to derive a CPR that discriminates women who would benefit from sexual health discussion and intervention. Participants were recruited to a cross-sectional survey from six GPs in a city in South-East England in 2016. On arrival, female patients aged 16-44 years were invited to complete a questionnaire that addressed psychosocial factors, and the following self-reported outcomes: 2+ sexual partners in the last year (2PP) and RUIP. For each sexual risk, psychosocial questions were retained from logistic regression modelling which best discriminated women at risk using the C-statistic. Sensitivity and specificity were established in consultation with GP staff. The final sample comprised N = 1238 women. 2PP was predicted by 11 questions including age, binge-drinking weekly, ever having a partner who insulted you often, current smoking, and not cohabiting (C-statistic = 0.83, sensitivity = 73% and specificity = 77%). RUIP was predicted by 5 questions including sexual debut <16 years, and emergency contraception use in the last 6 months (C-statistic = 0.70, sensitivity = 69% and specificity = 57%). 2PP was better discriminated than RUIP but neither to a clinically-useful degree. The finding that different psychosocial factors predicted each outcome has implications for prevention strategies. Further research should investigate causal links between psychosocial factors and sexual risk.

Assessing association between IWantTheKit risk quiz tool and sexually transmitted infection positivity in male users for sexually transmitted infection screening

Our previous pilot study during 2010-2013, based on the IWantTheKit (IWTK) home self-collection program for sexually transmitted infections (STIs), showed that voluntary risk score tool predicted STIs well in female volunteers compared to their male counterparts. Risk score became a required part of the IWTK program in August 2013. We investigated association of IWTK risk score and presence of STI in 592 male participants living in Maryland and Washington DC from August 2013 to April 2015. The risk score quiz includes questions on demographic and sexual risk behavior. Data were analyzed using the Cochran-Armitage test for trend to determine if prevalence of STIs (Chlamydia, gonorrhea, or trichomoniasis) increased with the higher risk score category. Overall, 57% of participants were aged < 30 years (mean: 30.1 ± 9.3 years); 42% white, 42% black, and 16% other races. The majority (67%) of participants had medium risk scores of 3-6, followed by high scores of 7-10 (22%), and 0-2 (11%). The overall prevalence of STIs was 10.5% (62/592). The prevalence of STIs was 3.1% for users with risk scores of 0-2, 10.4% for those with scores 3-6, and 14.3% for those with scores 7-10 (trend test: p = 0.019). Medium and high IWTK risk scores successfully predicted the probability of STIs in male participants after elimination of potential selection biases.

Can psychosocial and socio-demographic questions help identify sexual risk among heterosexually-active women of reproductive age? Evidence from Britain's third National Survey of Sexual Attitudes and Lifestyles (Natsal-3)

Background

Contraceptive advice and supply (CAS) and sexually transmitted infection (STI) testing are increasingly provided in primary care. Most risk assessment tools are based on sexual risk behaviours and socio-demographics, for use online or in specialist services. Combining socio-demographic and psychosocial questions (e.g. religious belief and formative experience) may generate an acceptable tool for targeting women in primary care who would benefit from intervention. We aimed to identify psychosocial and socio-demographic factors associated with reporting key sexual risk behaviours among women in the British general population.

Methods

We undertook complex survey analysis of data from 4911 hetero-sexually active women aged 16–44 years, who participated in Britain’s third National Survey of Sexual Attitudes and Lifestyles (Natsal-3), a national probability sample survey undertaken 2010–2012. We used multivariable regression to examine associations between the available psychosocial and socio-demographic variables in Natsal-3 and reports of three key sexual behaviours: a) 2+ partners in the last year (2PP); b) non-use of condoms with 2+ partners in the last year (2PPNC); c) non-use of condoms at first sex with most recent sexual partner (FSNC). We adjusted for key socio-demographic factors: age, ethnicity and socio-economic status (measured by housing tenure).

Results

Weekly binge drinking (6+ units on one occasion), and first sex before age 16 were each positively associated with all three sexual behaviours after adjustment. Current relationship status, reporting drug use (ever), younger age and living in rented accommodation were also associated with 2+ partners and 2 + partners without condoms after adjustment. Currently being a smoker, older age and respondent ethnicity were associated with FSNC after adjustment for all other variables. Current smoking status, treatment for depression (last year), and living at home with both parents until the age of 14 were each associated with one or more of the behaviours.

Conclusions

Reported weekly binge drinking, early sexual debut, and age group may help target STI testing and/or CAS among women. Further research is needed to examine the proportion of sexual risk explained by these factors, the acceptability of these questions to women in primary care and the need to customise them for community and other settings.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-3918-8) contains supplementary material, which is available to authorized users.

Screening for genital chlamydia infection

BACKGROUND

Genital infections caused by Chlamydia trachomatis are the most prevalent bacterial sexually transmitted infection worldwide. Screening of sexually active young adults to detect and treat asymptomatic infections might reduce chlamydia transmission and prevent reproductive tract morbidity, particularly pelvic inflammatory disease (PID) in women, which can cause tubal infertility and ectopic pregnancy.

OBJECTIVES

To assess the effects and safety of chlamydia screening versus standard care on chlamydia transmission and infection complications in pregnant and non-pregnant women and in men.

SEARCH METHODS

We searched the Cochrane Sexually Transmitted Infections Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS, CINAHL, DARE, PsycINFO and Web of Science electronic databases up to 14 February 2016, together with World Health Organization International Clinical Trials Registry (ICTRP) and ClinicalTrials.gov. We also handsearched conference proceedings, contacted trial authors and reviewed the reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in adult women (non-pregnant and pregnant) and men comparing a chlamydia screening intervention with usual care and reporting on a primary outcome (C. trachomatis prevalence, PID in women, epididymitis in men or incidence of preterm delivery). We included non-randomised controlled clinical trials if there were no RCTs for a primary outcome.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, extracted data and assessed the risk of bias. We resolved disagreements by consensus or adjudication by a third reviewer. We described results in forest plots and conducted meta-analysis where appropriate using a fixed-effect model to estimate risk ratios (RR with 95% confidence intervals, CI) in intervention vs control groups. We conducted a pre-specified sensitivity analysis of the primary outcome, PID incidence, according to the risks of selection and detection bias.

MAIN RESULTS

We included six trials involving 359,078 adult women and men. One trial was at low risk of bias in all six specific domains assessed. Two trials examined the effect of multiple rounds of chlamydia screening on C. trachomatis transmission. A cluster-controlled trial in women and men in the general population in the Netherlands found no change in chlamydia test positivity after three yearly invitations (intervention 4.1% vs control 4.3%, RR 0.96, 95% CI 0.84 to 1.09, 1 trial, 317,304 participants at first screening invitation, low quality evidence). Uptake of the intervention was low (maximum 16%). A cluster-randomised trial in female sex workers in Peru found a reduction in chlamydia prevalence after four years (adjusted RR 0.72, 95% CI 0.54 to 0.98, 1 trial, 4465 participants, low quality evidence).Four RCTs examined the effect of chlamydia screening on PID in women 12 months after a single screening offer. In analysis of four trials according to the intention-to-treat principle, the risk of PID was lower in women in intervention than control groups, with little evidence of between-trial heterogeneity (RR 0.68, 95% CI 0.49 to 0.94, I2 7%, 4 trials, 21,686 participants, moderate quality evidence). In a sensitivity analysis, the estimated effect of chlamydia screening in two RCTs at low risk of detection bias (RR 0.80, 95% CI 0.55 to 1.17) was compatible with no effect and was lower than in two RCTs at high or unclear risk of detection bias (RR 0.42, 95% CI 0.22 to 0.83).The risk of epididymitis in men invited for screening, 12 months after a single screening offer, was 20% lower risk for epididymitis than in those not invited; the confidence interval was wide and compatible with no effect (RR 0.80, 95% CI 0.45 to 1.42, 1 trial, 14,980 participants, very low quality evidence).We found no RCTs of the effects of chlamydia screening in pregnancy and no trials that measured the harms of chlamydia screening.

AUTHORS' CONCLUSIONS

Evidence about the effects of screening on C. trachomatis transmission is of low quality because of directness and risk of bias. There is moderate quality evidence that detection and treatment of chlamydia infection can reduce the risk of PID in women at individual level. There is an absence of RCT evidence about the effects of chlamydia screening in pregnancy.Future RCTs of chlamydia screening interventions should determine the effects of chlamydia screening in pregnancy, of repeated rounds of screening on the incidence of chlamydia-associated PID and chlamydia reinfection in general and high risk populations.

An assessment of population-based screening guidelines versus clinical prediction rules for chlamydia and gonorrhea case finding

INTRODUCTION

Much remains to be learned regarding the epistemology and utility of guidelines and clinical prediction rules (CPR), as well as the extent to which knowledge about risk at a population level might be pertinent to any given patient in terms of case finding accuracy. In the current paper, we offer an empirical examination that juxtaposes population-based guidelines and CPR for sexual health decision-making.

MATERIALS AND METHODS

We analyzed electronic medical records from asymptomatic patient visits involving tests for chlamydia or gonorrhea between 2000 and 2012 at nine publicly funded STI clinics in British Columbia to compare the case-finding accuracy for infection risk under two scenarios: (1) if the population had been screened using the Public Health Agency of Canada (PHAC) screening guidelines for chlamydia and gonorrhea; or (2) if the population has been screened using a CPR. Performance metrics evaluated included the area under the ROC curve (AUC).

RESULTS

In total, 35,818 individuals met the study inclusion criteria. The overall infection rate was 3.0%. Using the PHAC guidelines, the discriminatory performance of using any versus no risk factors and counts of risk factors were: AUC=0.55, 95% CI: 0.54-0.56 and AUC=0.64, 95% CI: 0.63-0.66, respectively. The model used to derive the CPR demonstrated good discrimination (AUC=0.73, 95% CI: 0.71-0.74).

CONCLUSIONS

The current paper provides empirical evidence that demonstrates that population-based guidelines may not necessarily be a perfect fit for application at the individual level. Thus, we recommend risk estimation algorithms for use in sexual health services and programs.

Enteric disease episodes and the risk of acquiring a future sexually transmitted infection: a prediction model in Montreal residents

OBJECTIVE

The sexual transmission of enteric diseases poses an important public health challenge. We aimed to build a prediction model capable of identifying individuals with a reported enteric disease who could be at risk of acquiring future sexually transmitted infections (STIs).

MATERIALS AND METHODS

Passive surveillance data on Montreal residents with at least 1 enteric disease report was used to construct the prediction model. Cases were defined as all subjects with at least 1 STI report following their initial enteric disease episode. A final logistic regression prediction model was chosen using forward stepwise selection.

RESULTS

The prediction model with the greatest validity included age, sex, residential location, number of STI episodes experienced prior to the first enteric disease episode, type of enteric disease acquired, and an interaction term between age and male sex. This model had an area under the curve of 0.77 and had acceptable calibration.

DISCUSSION

A coordinated public health response to the sexual transmission of enteric diseases requires that a distinction be made between cases of enteric diseases transmitted through sexual activity from those transmitted through contaminated food or water. A prediction model can aid public health officials in identifying individuals who may have a higher risk of sexually acquiring a reportable disease. Once identified, these individuals could receive specialized intervention to prevent future infection.

CONCLUSION

The information produced from a prediction model capable of identifying higher risk individuals can be used to guide efforts in investigating and controlling reported cases of enteric diseases and STIs.

Prediction of Chlamydia trachomatis infection to facilitate selective screening on population and individual level: a cross-sectional study of a population-based screening programme

OBJECTIVES

To develop prediction models for Chlamydia trachomatis (Ct) infection with different levels of detail in information, that is, from readily available data in registries and from additional questionnaires.

METHODS

All inhabitants of Rotterdam and Amsterdam aged 16-29 were invited yearly from 2008 until 2011 for home-based testing. Their registry data included gender, age, ethnicity and neighbourhood-level socioeconomic status (SES). Participants were asked to fill in a questionnaire on education, sexually transmitted infection history, symptoms, partner information and sexual behaviour. We developed prediction models for Ct infection using first-time participant data-including registry variables only and with additional questionnaire variables-by multilevel logistic regression analysis to account for clustering within neighbourhoods. We assessed the discriminative ability by the area under the receiver operating characteristic curve (AUC).

RESULTS

Four per cent (3540/80 385) of the participants was infected. The strongest registry predictors for Ct infection were young age (especially for women) and Surinamese, Antillean or sub-Saharan African ethnicity. Neighbourhood-level SES was of minor importance. Strong questionnaire predictors were low to intermediate education level, ethnicity of the partner (non-Dutch) and having sex with casual partners. When using a prediction model including questionnaire risk factors (AUC 0.74, 95% CI 0.736 to 0.752) for selective screening, 48% of the participating population needed to be screened to find 80% (95% CI 78.4% to 81.0%) of Ct infections. The model with registry risk factors only (AUC 0.67, 95% CI 0.656 to 0.675) required 60% to be screened to find 78% (95% CI 76.6% to 79.4%) of Ct infections.

CONCLUSIONS

A registry-based prediction model can facilitate selective Ct screening at population level, with further refinement at the individual level by including questionnaire risk factors.

Deriving and validating a risk estimation tool for screening asymptomatic chlamydia and gonorrhea

BACKGROUND

There has been considerable interest in the development of innovative service delivery modules for prioritizing resources in sexual health delivery in response to dwindling fiscal resources and rising infection rates.

METHODS

This study aims to derive and validate a risk scoring algorithm to accurately identify asymptomatic patients at increased risk for chlamydia and/or gonorrhea infection. We examined the electronic records of patient visits at sexual health clinics in Vancouver, Canada. We derived risk scores from regression coefficients of multivariable logistic regression model using visits between 2000 and 2006. We evaluated the model's discrimination, calibration, and screening performance. Temporal validation was assessed in visits from 2007 to 2012.

RESULTS

The prevalence of infection was 1.8% (n = 10,437) and 2.1% (n = 14,956) in the derivation and validation data sets, respectively. The final model included younger age, nonwhite ethnicity, multiple sexual partners, and previous infection and showed reasonable performance in the derivation (area under the receiver operating characteristic curve = 0.74; Hosmer-Lemeshow P = 0.91) and validation (area under the receiver operating characteristic curve = 0.64; Hosmer-Lemeshow P = 0.36) data sets. A risk score cutoff point of at least 6 detected 91% and 83% of cases by screening 68% and 68% of the derivation and validation populations, respectively.

CONCLUSIONS

These findings support the use of the algorithm for individualized risk assessment and have important implications for reducing unnecessary screening and saving costs. Specifically, we anticipate that the algorithm has potential uses in alternative settings such as Internet-based testing contexts by facilitating personalized test recommendations, stimulating health care-seeking behavior, and aiding risk communication by increasing sexually transmitted infection risk perception through the creation of tailored risk messages to different groups.

Use of a risk quiz to predict infection for sexually transmitted infections: a retrospective analysis of acceptability and positivity

BACKGROUND

Individuals who are sexually active may want to make a decision as to whether they are at risk for having a sexually transmitted infection (STI) such as Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis. Our goal was to develop and evaluate a simple self-taken sexual risk quiz for participants, ordering an online STI self-collection test kit to determine whether the score predicted infection status.

METHODS

As part of the IWantTheKit programme for home sample self-collection for STIs, 2010-2013, the programme asked male and female users to voluntarily take a risk quiz. The six-question quiz was about risk behaviour and included an age question. Data analyses were stratified by gender as determined a priori. Scores 0-10 were stratified into risk groups for each gender based on similar risk score-specific STI prevalence. Retrospective analyses were performed to assess whether risk group predicted aggregate STI positivity. Urogenital/rectal mailed samples were tested by nucleic acid amplification tests.

RESULTS

More females (N=836) than males (N=558) provided voluntary risk scores. The percentage of eligible participants who submitted scores was 43.9% for both females and males. There was a higher STI infection rate in females (14.0%) than in males (7.0%) for having any STI (p<0.001). Multivariate logistic analysis for females, which controlled for age and race, demonstrated that a higher risk score group independently predicted risk for having an STI (OR of 2.2 for risk scores 5-7 and 4.2 OR for scores of 8-10). For males, the multivariate model, which controlled for race, indicated that no risk score group was associated having an STI.

CONCLUSIONS

Results of a participant's own sexual risk quiz score independently predicted STI positivity for women, but not for men. Further study of this simple risk quiz is required.

Socioeconomic factors and other sources of variation in the prevalence of genital chlamydia infections: A systematic review and meta-analysis

Background

The success of chlamydia screening programmes relies on their ability to effectively target those with greatest need. Young people from disadvantaged backgrounds may be at greater need for chlamydia screening, but existing evidence on the variation of prevalence with social position is inconclusive. We carried out a systematic review to examine variation in chlamydia prevalence in populations and possible sources of this variation.

Methods

Studies were eligible if they reported chlamydia prevalence derived from population-based samples that included young people aged 15–24 years from Europe, North America or Australia. Systematic searches of the following databases were undertaken from their inception to November 2014: MEDLINE, Embase, Web of Science and PsychINFO. There were no restrictions by language or publication date. Independent screening for eligibility and data extraction were carried out by two reviewers. Where possible, data were pooled in a meta-analysis using a random effects model. Heterogeneity was further investigated using meta-regression techniques.

Results

Of 1248 unique titles and abstracts and 263 potentially relevant full texts, 29 studies were eligible for inclusion. There was relatively strong evidence that disadvantaged young people had an increased risk of having a chlamydia infection across multiple measures of disadvantage, including lower educational attainment (OR 1.94, 95 % CI: 1.52 to 2.47), lower occupational class (OR 1.49, 95 % CI: 1.07 to 2.08) and residence in deprived areas (OR 1.76, 95 % CI: 1.15 to 2.71) with an overall OR of 1.66 (95 % CI: 1.37 to 2.02). Socioeconomic disadvantage was associated with chlamydia infection in both men and women. There was weaker evidence that prevalence estimates also varied by gender and age.

Conclusions

This review provides evidence of a consistent association between socioeconomic disadvantage and higher risk of Chlamydia infection. This association may reflect a number of factors including social variation in engagement with Chlamydia control programmes. Chlamydia screening could therefore reduce or increase health inequalities, depending on service provision and uptake by different socioeconomic groups.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2069-7) contains supplementary material, which is available to authorized users.

Chlamydia trachomatis infection in young adults - association with concurrent partnerships and short gap length between partners

BACKGROUND

Sexually transmitted infections (STIs) continue to be highly prevalent in young people. New understanding of sexual risk behaviour is essential for future preventive initiatives. Studies based on self-reported STI history indicate that gap length between sexual partnerships is an important determinant in STI transmission, but little is known about the impact of concurrent partnerships and short gap length. This study aimed to examine the significance of concurrent partnerships and short gap length between serially monogamous partnerships in Chlamydia trachomatis-infected individuals compared to the general population.

METHODS

A Danish cross-sectional study was conducted among individuals aged 15-29 years with a verified C. trachomatis infection and a sample of the background population. Participants answered a web-based questionnaire on sexual behaviour. Associations were identified in multivariate analyses.

RESULTS

In total, 36% of the included young adults reported that they had two or more partners within the last year. Concurrent partnerships were frequent (46%), and the gap length between serially monogamous partnerships tended to be short (median gap length, 64 days, interquartile interval (IQI) = 31, 122). A strong association was found between concurrent partnerships (odds ratio (OR) = 12.5, 95% confidence interval (CI) = 7.7-20.4), short gap length between serially monogamous partnerships (OR = 10.0, 95% CI = 5.7-17.4) and having a verified C. trachomatis infection.

CONCLUSIONS

C. trachomatis infection was strongly associated with concurrent partnerships or short gap length between serially monogamous partnerships. These findings have considerable implications for public health policy. Both types of risk factors should be considered in future preventive interventions aiming to reduce the spread of C. trachomatis infections.

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.

Electronic supplementary material

The online version of this article (doi:10.1186/s12875-015-0281-2) contains supplementary material, which is available to authorized users.

High-resolution multilocus sequence typing reveals novel urogenital Chlamydia trachomatis strains in women in Mopani district, South Africa

OBJECTIVES

Recently, we reported a high prevalence (16%) of urogenital Chlamydia trachomatis infections among women in a rural setting in South Africa. Molecular epidemiological studies on C. trachomatis infections could provide insights into the characteristics of this epidemic, yet such data are not available. The objective of this study was therefore to assess the distribution of C. trachomatis strains among women from a South African rural community, the Mopani district, and to compare it with strains from Amsterdam, the Netherlands.

METHODS

High-resolution multilocus sequence typing (hr-MLST) was used to study urogenital C. trachomatis infections in women visiting primary healthcare facilities across rural Mopani District in Limpopo Province, South Africa. Sequence types (STs) were compared with 100 strains from women visiting the sexually transmitted infection clinic in Amsterdam, the Netherlands.

RESULTS

Full hr-MLST data were obtained for C. trachomatis infection in 43 women from Mopani district. Using the complete hr-MLST profile of all 43 women from Mopani district, 26 STs could be identified, of which 18 (69%) were novel to the hr-MLST database. The remaining STs clustered together with strains from Amsterdam.

CONCLUSIONS

Hr-MLST data revealed a diverse molecular epidemiology with novel STs and a specific cluster for the Mopani district. Also C. trachomatis types that occur worldwide were detected.

Identification and risk assessment of Swedish youth at risk of chlamydia

AIMS

The aim of the study was to identify youth at high risk of chlamydia including variables related to sexual health and negative experiences of sexuality.

METHODS

In late 2009, a questionnaire on sexuality was answered by Swedish youth. The study sample was self-selected from different Internet communities. Data from 6544 sexually active participants, aged 15-24 years, were analyzed in a multivariable logistic regression model. Discriminative power was measured by the area under the receiver operating characteristic curve.

RESULTS

In the univariate analysis, self-reported chlamydia was associated with most risk behavior variables, experience of coerced sex, and reimbursement for sex, with slight gender variation. The factors that best predicted self-reported chlamydia among females were number of partners, age, and having been reimbursed for sex. Among males, the number of partners and alcohol consumption were the strongest predictors. Increasing number of partners up to 10 during the past 12 months was the most important predictor for both genders. A skewed distribution of chlamydia was demonstrated, in that 37.6% of cases in females and 38.6% in males were estimated to occur among a tenth of the population.

CONCLUSIONS

Testing, prevention, and care for chlamydia should be directed toward those most at risk, as they account for a large proportion of the total number of chlamydia cases. The special needs of the high-risk group need to be acknowledged and chlamydia regarded as a possible marker for risk behavior and negative sexuality experiences.

A critical appraisal of risk models for predicting sexually transmitted infections

BACKGROUND

Prediction rules have been proposed as alternatives to screening recommendations and have potential applications in sexual health decision making. To our knowledge, there has been no review undertaken providing a critical appraisal of existing prediction rules in sexual health contexts. This review aims to identify and characterize prediction rules developed and validated for sexually transmitted infection (STI) screening, describe the methodological issues essential to the suitability of derived models for clinical or public health application, and synthesize the literature on the performance of these models.

METHODS

We searched MEDLINE (2003-2012) to identify studies that reported on models predicting STIs. We explored the methodological quality of the studies based on a 16-item quality assessment checklist. We also evaluated the studies based on data extracted on model discrimination, calibration, sensitivity, and testing efficiency.

RESULTS

We identified 16 publications reporting on STI prediction rules. The most poorly addressed quality items were missing values, calibration measures, and variable definition. Overall, the performance of risk models as measured by discrimination (area under the receiver operating characteristic curve range, 0.64-0.88) and calibration was found to be generally good or satisfactory. Eight studies attained or were close to attaining the performance benchmark of testing less than 60% of the target population to achieve 90% sensitivity. The 2 risk models that were externally validated displayed adequate discrimination in new settings.

CONCLUSIONS

Although we identified several well-performing STI risk prediction rules, few have been validated. Future developments in the use of prediction rules should address their clinical consequence, comparative usefulness, external validity, and implementation impact.

Predictors identifying those at increased risk for STDs: a theory-guided review of empirical literature and clinical guidelines

SummarySexually transmitted diseases (STDs) are leading causes of substantial morbidity worldwide. Identification of risk factors for estimating STD risk provides opportunities for optimising service delivery in clinical settings, including improving case finding accuracy and increasing cost-efficiency by limiting the testing of low-risk individuals. The current study was undertaken to synthesise the evidence supporting commonly cited chlamydia and gonorrhoea risk factors. The level of empirical support for the following predictors was strong/moderate: age, race/ethnicity, multiple lifetime sexual partners, sex with symptomatic partners and concurrent STD diagnosis. The following predictors had weak evidence: socio-economic status, transactional sex, drug/alcohol use, condom use and history of STD diagnosis. The most frequently listed predictors among nine clinical guidelines were younger age and multiple sexual partners; the least consistently listed predictor was inconsistent condom use. We found reasonably good concordance between risk factors consistently listed in the recommendations and predictors found to have strong empirical support in the literature. There is a need to continue building the evidence base to explicate the mechanisms and pathways of STD acquisition. We recommend periodic reviews of the level of support of predictors included in clinical guidelines to ensure that they are in accordance with empirical evidence.

Prevalence of chlamydia in young adulthood and association with life course socioeconomic position: birth cohort study

BACKGROUND

Few estimates are available of chlamydia prevalence in the general population. Existing studies have limited scope to explore potential selection bias or associations with socioeconomic position.

METHODS

We examined the prevalence of Chlamydia trachomatis infection and associations with life-course socioeconomic position in the Avon Longitudinal Study of Parents and Children in England. Chlamydia infection was measured through nucleic acid amplification test of urine specimens.

RESULTS

4864 (51%) of those invited attended the clinic (mean age 17.8; SD 0.37 years). (60%) provided a urine specimen. Prevalence was 1.0% (95% CI 0.6 to 1.6) among participants reporting sexual activity. Risk of infection was strongly associated with life course social disadvantage and with recent sexual behaviour. After adjustment for other measures of disadvantage and for sexual behaviour the strongest risk factors for infection were lower maternal educational attainment (OR 9.1 (1.1, 76.7)) and lower participant educational attainment at age 11 (OR 5.0 (1.5, 16.5)). Both clinic attendance and agreement to test were lower amongst the disadvantaged. Adjustment for selective participation based on detailed information on non-participants approximately doubled prevalence estimates. Prevalence was higher in sexually active women (1.4% (0.7 to 2.4) than men (0.5% (0.1 to 1.3)).

CONCLUSIONS

Chlamydia prevalence in this general population sample was low even after adjustment for selective participation in testing. These estimates of prevalence and patterns of association with socioeconomic position may both reflect recent screening efforts. Prevalence was higher amongst the disadvantaged who were also less likely to engage in testing. Our results reveal the importance of monitoring and addressing inequalities in screening programme participation and outcomes.

Knowledge and acceptability of Chlamydia trachomatis screening among pregnant women and their partners; a cross-sectional study

Background

Chlamydia trachomatis infections in pregnancy can cause maternal disease, adverse pregnancy outcomes and neonatal disease, which is why chlamydia screening during pregnancy has been advocated. The effectiveness of a screening program depends on the knowledge of health care professionals, women and partners and the acceptability for screening of the target population. We assessed the knowledge of chlamydia infection among pregnant women and their partners in the Netherlands, their attitudes towards testing, and their experiences of being offered a chlamydia test. In addition, we evaluated the association between participants’ background characteristics and knowledge of chlamydia.

Methods

Pregnant women aged ≤ 30 years and their partners (regardless of their age) attending one of the participating primary midwifery care practices in the Netherlands were invited to participate. All participants completed a questionnaire, pregnant women provided a vaginal swab and partners provided a urine sample to test for C. trachomatis.

Results

In total, 383 pregnant women and 282 partners participated in the study of whom 1.9% women and 2.6% partners tested chlamydia positive. Participants had high levels of awareness (92.8%) of chlamydial infection. They were knowledgeable about the risk of chlamydia infection; median knowledge score was 9.0 out of 12.0. Lower knowledge scores were found among partners (p-value <0.001), younger aged (p-value 0.02), non-western origin (p-value <0.001), low educational level (p-value <0.001), and no history of sexually transmitted infections (p-value <0.001). In total, 78% of respondents indicated that when pregnant women are tested for chlamydia, their partners should also be tested; 54% believed that all women should routinely be tested. Pregnant women more often indicated than partners that testing partners for chlamydial infection was not necessary (p-value <0.001). The majority of pregnant women (56.2%) and partners (59.2%) felt satisfied by being offered the test during antenatal care.

Conclusion

Pregnant women and their partners were knowledgeable about chlamydial infection, found testing, both pregnant women and their partners, for chlamydia acceptable and not stigmatizing.

Risk prediction in sexual health contexts: protocol

BACKGROUND

In British Columbia (BC), we are developing Get Checked Online (GCO), an Internet-based testing program that provides Web-based access to sexually transmitted infections (STI) testing. Much is still unknown about how to implement risk assessment and recommend tests in Web-based settings. Prediction tools have been shown to successfully increase efficiency and cost-effectiveness of STI case finding in the following settings.

OBJECTIVE

This project was designed with three main objectives: (1) to derive a risk prediction rule for screening chlamydia and gonorrhea among clients attending two public sexual health clinics between 2000 and 2006 in Vancouver, BC, (2) to assess the temporal generalizability of the prediction rule among more recent visits in the Vancouver clinics (2007-2012), and (3) to assess the geographical generalizability of the rule in seven additional clinics in BC.

METHODS

This study is a population-based, cross-sectional analysis of electronic records of visits collected at nine publicly funded STI clinics in BC between 2000 and 2012. We will derive a risk score from the multivariate logistic regression of clinic visit data between 2000 and 2006 at two clinics in Vancouver using newly diagnosed chlamydia and gonorrhea infections as the outcome. The area under the receiver operating characteristic curve (AUC) and the Hosmer-Lemeshow statistic will examine the model's discrimination and calibration, respectively. We will also examine the sensitivity and proportion of patients that would need to be screened at different cutoffs of the risk score. Temporal and geographical validation will be assessed using patient visit data from more recent visits (2007-2012) at the Vancouver clinics and at clinics in the rest of BC, respectively. Statistical analyses will be performed using SAS, version 9.3.

RESULTS

This is an ongoing research project with initial results expected in 2014.

CONCLUSIONS

The results from this research will have important implications for scaling up of Internet-based testing in BC. If a prediction rule with good calibration, discrimination, and high sensitivity to detect infection is found during this project, the prediction rule could be programmed into GCO so that the program offers individualized testing recommendations to clients. Further, the prediction rule could be adapted into educational materials to inform other Web-based content by creating awareness about STI risk factors, which may stimulate health care seeking behavior among individuals accessing the website.

Chlamydia prevalence in the general population: is there a sex difference? a systematic review

Background

The focus of Chlamydia trachomatis screening and testing lies more on women than on men. The study aim was to establish by systematic review the prevalence of urogenital Chlamydia trachomatis infection in men and women in the general population.

Methods

Electronic databases and reference lists were searched from 2000 to 2013 using the key words “Chlamydia trachomatis”, “population-based study” and “disease prevalence”. Reference lists were checked. Studies were included in the analysis if Chlamydia trachomatis prevalence was reported for both men and women in a population-based study. Prevalence rates for men and women were described as well as highest prevalence rate by age and sex. The difference in prevalence between the sexes in each study was calculated.

Results

Twenty-five studies met the inclusion criteria and quality assessment for the review. In nine of the twenty-five studies there was a statistically significant sex difference in the chlamydia prevalence. In all nine studies the prevalence of chlamydia was higher in women than in men. The prevalence for women varied from 1.1% to 10.6% and for men from 0.1% to 12.1%. The average chlamydia prevalence is highly variable between countries. The highest prevalence of chlamydia occurred predominantly in younger age groups (< 25 years). The absence of symptoms in population-based urogenital chlamydia infection is common in men and women (mean 88.5% versus 68.3%).

Conclusions

The urogenital chlamydia trachomatis prevalence in the general population is more similar than dissimilar for men and women. A modest sex difference is apparent. The prevalence rates can be used to inform chlamydia screening strategies in general practice.

Higher Chlamydia trachomatis prevalence in ethnic minorities does not always reflect higher sexual risk behaviour

Background

In affluent countries, the prevalence of Chlamydia trachomatis (CT) is often higher in certain ethnic minorities than in the majority population. In the Netherlands, we examined why CT prevalence is higher in Surinamese/Antilleans, the largest minority in the country.

Methods

Heterosexuals were recruited for a cross-sectional survey from May through August 2010 at the sexually transmitted infections (STI) clinic in Amsterdam. Participants completed a questionnaire and were tested for STI. A causal directed acyclic graph was assumed to investigate whether the association between ethnicity and CT could be explained by differences in sexual risk behaviour and socio-economic status.

Results

Subjects included 1044 with Dutch background and 335 with Surinamese/Antillean background. Median age for the combined population was 25 (IQR 22-30) years, and 55.4% was female. Sexual risk behaviour did not differ significantly between the two groups. CT was diagnosed in 17.9% of Surinamese/Antilleans and in 11.4% of Dutch. Surinamese/Antilleans were significantly more likely to have CT (OR 1.70; 95% CI 1.21-2.38). The association between ethnicity and CT remained statistically significant after adjusting for sexual risk behaviour, age, sex, and ethnic mixing (aOR 1.48; 95% CI 1.00-2.18), but not after adjusting for education and neighbourhood, markers of socio-economic status (aOR 1.08; 95% CI 0.71-1.64).

Conclusion

The difference in CT prevalence between the minority and majority groups was not explained by differences in sexual risk behaviour. The higher CT prevalence found among Surinamese/Antilleans appeared to reflect their lower educational level and neighbourhood, two markers of lower socio-economic status. We hypothesise that the effect results from lower health-seeking behaviour.

Effects of population based screening for Chlamydia infections in the Netherlands limited by declining participation rates

Background

A large trial to investigate the effectiveness of population based screening for chlamydia infections was conducted in the Netherlands in 2008–2012. The trial was register based and consisted of four rounds of screening of women and men in the age groups 16–29 years in three regions in the Netherlands. Data were collected on participation rates and positivity rates per round. A modeling study was conducted to project screening effects for various screening strategies into the future.

Methods and Findings

We used a stochastic network simulation model incorporating partnership formation and dissolution, aging and a sexual life course perspective. Trends in baseline rates of chlamydia testing and treatment were used to describe the epidemiological situation before the start of the screening program. Data on participation rates was used to describe screening uptake in rural and urban areas. Simulations were used to project the effectiveness of screening on chlamydia prevalence for a time period of 10 years. In addition, we tested alternative screening strategies, such as including only women, targeting different age groups, and biennial screening. Screening reduced prevalence by about 1% in the first two screening rounds and leveled off after that. Extrapolating observed participation rates into the future indicated very low participation in the long run. Alternative strategies only marginally changed the effectiveness of screening. Higher participation rates as originally foreseen in the program would have succeeded in reducing chlamydia prevalence to very low levels in the long run.

Conclusions

Decreasing participation rates over time profoundly impact the effectiveness of population based screening for chlamydia infections. Using data from several consecutive rounds of screening in a simulation model enabled us to assess the future effectiveness of screening on prevalence. If participation rates cannot be kept at a sufficient level, the effectiveness of screening on prevalence will remain limited.

Determinants of intention to get tested for STI/HIV among the Surinamese and Antilleans in the Netherlands: results of an online survey

BACKGROUND

High infection rates of STIs are found among the different ethnic communities living in the Netherlands, especially among the Surinamese and Dutch-Antilleans. Only limited effective interventions that promote STI/HIV testing among these communities are available in the Netherlands. In the present study we identified the determinants of the intention to get tested for STI/HIV of the sexually active Surinamese and Dutch-Antilleans living in the Netherlands. Secondly, this study assesses which determinants should be addressed when promoting STI/HIV testing among these communities.

METHODS

In total, 450 Surinamese and 303 Dutch-Antillean respondents were recruited through Dutch Internet panels and group activities. The questionnaire used in the online survey was based on the concepts of the Health Belief Model, the Social Cognitive Theory, and Theory of Planned behavior. To correct for multiple outcome testing, we considered differences as statistically significant at p<.01 for all analyses. For the multivariate linear regression analysis, variables that were significant were entered into the model block-wise.

RESULTS

Health motivation, cues to action, subjective norms, risk behavior, test history, open communication about sexuality, and marital status were important (univariate) predictors of the intention to get tested for STI/HIV for both the Surinamese and Dutch-Antillean respondents. For both the Surinamese and Dutch-Antilleans, subjective norms were the most salient predictor of the intention to get tested in multivariate analyses, explaining 10% and 13% of the variance respectively; subjective norms had a direct influence on the intention for both the Surinamese and the Dutch-Antilleans.

CONCLUSIONS

The strong correlation and predictive power of subjective norms on the intention to get tested for STI/HIV, endorses the importance of focusing on community-based intervention rather than focusing on personal determinants, to change the present perceptions and attitudes towards testing. Health promoting programs should be aimed at promoting open communication regarding sexuality and testing. Stimulating each other to get tested frequently could also help achieving the desired behavior.

Effectiveness of yearly, register based screening for chlamydia in the Netherlands: controlled trial with randomised stepped wedge implementation

OBJECTIVE

To evaluate the effectiveness of register based, yearly chlamydia screening.

DESIGN

Controlled trial with randomised stepped wedge implementation in three blocks.

SETTING

Three regions of the Netherlands: Amsterdam, Rotterdam, and South Limburg.

PARTICIPANTS

317 304 women and men aged 16-29 years listed on municipal registers at start of trial.

INTERVENTION

From March 2008 to February 2011, the Chlamydia Screening Implementation programme offered yearly chlamydia screening tests. Postal invitations asked people to use an internet site to request a kit for self collection of samples, which would then be sent to regional laboratories for testing. Treatment and partner notification were done by the general practitioner or at a sexually transmitted infection clinic.

MAIN OUTCOME MEASURES

Primary outcomes were the percentage of chlamydia tests positive (positivity), percentage of invitees returning a specimen (uptake), and estimated chlamydia prevalence. Secondary outcomes were positivity according to sex, age, region, and sociodemographic factors; adherence to screening invitations; and incidence of self reported pelvic inflammatory disease.

RESULTS

The participation rate was 16.1% (43 358/269 273) after the first invitation, 10.8% after the second, and 9.5% after the third, compared with 13.0% (6223/48 031) in the control block invited at the end of round two of the intervention. Chlamydia positivity in the intervention blocks at the first invitation was the same as in the control block (4.3%) and 0.2% lower at the third invitation (odds ratio 0.96 (95% confidence interval 0.83 to 1.10)). No substantial decreases in positivity were seen after three screening rounds in any region or sociodemographic group. Among the people who participated three times (2.8% of all invitees), positivity fell from 5.9% to 2.9% (odds ratio 0.49 (0.47 to 0.50)).

CONCLUSIONS

There was no statistical evidence of an impact on chlamydia positivity rates or estimated population prevalence from the Chlamydia Screening Implementation programme after three years at the participation levels obtained. The current evidence does not support a national roll out of this register based chlamydia screening programme.

TRIAL REGISTRATION

NTR 3071 (Netherlands Trial Register, www.trialregister.nl).

Population based study of genital Chlamydia trachomatis prevalence and associated factors in Norway: a cross sectional study

Background

The number of diagnosed cases of Chlamydia trachomatis infection has been increasing in the past years in Norway although the testing rate has been relatively stable. The aim of this study was to measure the prevalence of genital Chlamydia trachomatis in young men and women in one county in Norway and determine associated factors in order to better target preventive measures.

Methods

We mailed to a random sample of 10 000 persons aged 18–25 in Rogaland county a mail-back urine sample kit and a self-administered questionnaire with questions on socio-demographic details, health seeking behaviour and symptoms of and history of sexually transmitted diseases. Associations between current Clamydia trachomatis infection and the above mentioned factors were studied by multiple logistic regression.

Results

The response rate among women was 18.9% (930/4923) and 11.9% (605/5077) among men. The prevalence of Chlamydia trachomatis infection was 5.8% (95% CI 4.5-6.8) among women and 5.1% (95% CI 3.8-6.8) among men. For men a greater number of partners during the last year (p for trend < 0.001), and living in a municipality without a local youth clinic increased the odds of infection (OR 8.6, 95% CI 2.2-33.9). For women a greater number of partners during the last year (p < 0.001) and not having consulted a family doctor for STIs (OR 2.1 95% CI 1.1-4.2) were positively associated with infection while not having a previous Chlamydia trachomatis diagnosis decreased the odds of having this infection (OR 0.3, 95% CI 0.2-0.7).

Conclusion

Our results indicate the importance of having a visible youth clinic in each municipality. It also suggests targeting women who have had a previous Chlamydia trachomatis infection diagnosed before.

Promoting STI testing among senior vocational students in Rotterdam, the Netherlands: effects of a cluster randomized study

BACKGROUND

Adolescents are a risk group for acquiring sexually transmitted infections (STIs). In the Netherlands, senior vocational school students are particular at risk. However, STI test rates among adolescents are low and interventions that promote testing are scarce. To enhance voluntary STI testing, an intervention was designed and evaluated in senior vocational schools. The intervention combined classroom health education with sexual health services at the school site. The purpose of this study was to assess the combined and single effects on STI testing of health education and school-based sexual health services.

METHODS

In a cluster-randomized study the intervention was evaluated in 24 schools, using three experimental conditions: 1) health education, 2) sexual health services; 3) both components; and a control group. STI testing was assessed by self reported behavior and registrations at regional sexual health services. Follow-up measurements were performed at 1, 3, and 6-9 months. Of 1302 students present at baseline, 739 (57%) completed at least 1 follow-up measurement, of these students 472 (64%) were sexually experienced, and considered to be susceptible for the intervention. Multi-level analyses were conducted. To perform analyses according to the principle of intention-to-treat, missing observations at follow-up on the outcome measure were imputed with multiple imputation techniques. Results were compared with the complete cases analysis.

RESULTS

Sexually experienced students that received the combined intervention of health education and sexual health services reported more STI testing (29%) than students in the control group (4%) (OR = 4.3, p < 0.05). Test rates in the group that received education or sexual health services only were 5.7% and 19.9%, not reaching statistical significance in multilevel analyses. Female students were more often tested then male students: 21.5% versus 5.4%. The STI-prevalence in the study group was low with 1.4%.

CONCLUSIONS

Despite a low dose of intervention that was received by the students and a high attrition, we were able to show an intervention effect among sexually experienced students on STI testing. This study confirmed our hypothesis that offering health education to vocational students in combination with sexual health services at school sites is more effective in enhancing STI testing than offering services or education only.

Improving STD testing behavior among high-risk young adults by offering STD testing at a vocational school

BACKGROUND

Chlamydia trachomatis infection (CT) is the most prevalent bacterial STD. Sexually active adolescents and young adults are the main risk group for CT. However, STD testing rates in this group are low since exposed individuals may not feel at risk, owing-at least in part-to the infection's largely asymptomatic nature. Designing new testing environments that are more appealing to young people who are most at risk of acquiring chlamydia can be an important strategy to improve overall testing rates. Here we evaluate the effect of a school-based sexual health program conducted among vocational school students, aiming to obtain better access for counseling and enhance students' STD testing behavior.

METHODS

Adolescents (median age 19 years) attending a large vocational school were provided with sexual health education. Students filled in a questionnaire measuring CT risk and were offered STD testing. Using univariate and multivariate analysis, we assessed differences between men and women in STD-related risk behavior, sexual problems, CT testing behavior and determinants of CT testing behavior.

RESULTS

Of 345 participants, 70% were female. Of the 287 sexually active students, 75% were at high risk for CT; one third of women reported sexual problems. Of sexually active participants, 61% provided a self-administered specimen for STD testing. Independent determinants for testing included STD related symptoms and no condom use. All CT diagnoses were in the high-CT-risk group. In the high-risk group, STD testing showed an increased uptake, from 27% (previous self-reported test) to 65% (current test). CT prevalence was 5.7%.

CONCLUSIONS

Vocational school students are a target population for versatile sexual health prevention. When provided with CT testing facilities and education, self selection mechanisms seemed to increase CT testing rate dramatically in this high-CT-risk population expressing sexual problems. Considering the relative ease of testing and treating large numbers of young adults, offering tests at a vocational school is feasible in reaching adolescents for STD screening. Although cost-effectiveness remains an issue counseling is effective in increasing test rates.

Sexual and reproductive health behaviors of undocumented migrants in Geneva: a cross sectional study

Undocumented migrants face major barriers in accessing prevention and health care. Whereas the association between low socioeconomic status and poor health is well documented only few studies have addressed specific health issues in undocumented migrants. The aim of the present study is to describe sexual and reproductive health behaviors of undocumented migrants in Geneva. This descriptive cross sectional study included consecutive undocumented migrants presenting from November 2007 to February 2008 to a health facility offering free access to health care to this population. Following informed consent, they completed a self administered questionnaire about their socio-demographic profile and sexual and reproductive health behaviors. A total of 384 patients were eligible for the study. 313 (82%) agreed to participate of which 77% (241 patients) completed the survey. Participants were mainly young, Latino-American, single, well-educated and currently working women. They had multiple partners and reported frequently engaging in sexual intercourse. Use of contraceptive methods and strategies of prevention against sexually transmitted infections (STI) were rare. Nearly half of the women had had at least one induced abortion and 40% had had an unplanned pregnancy. One in four participants reported a current or past STI or other genital infection. The results of our study suggest that undocumented migrants engage in frequent and high risk sexual intercourse with insufficient use of contraceptive methods and suboptimal strategies of prevention against STI. Our study underlines the real need for specific sexual and reproductive educational programs targeting this hard to reach population.

Asking about condom use: a key to individualized care when screening for chlamydia

Chlamydia trachomatis (CT) infection has been a target for both selective and national screening programmes, and Sweden has an opportunistic approach. A national plan of action states that risk groups should be identified and offered risk reduction counselling. Patients attending a drop-in sexually transmitted infection (STI) clinic reception at the University Hospital, Umeå, Sweden, were invited to complete a questionnaire regarding sociodemographic characteristics, symptoms and sexual risk behaviour; all had a CT test taken. A total of 1305 patients were included, 58% men, mean age 27.8 years. CT prevalence was 11%; 51% of those with CT were ≥25 years old. Only 5% used a condom during the entire sexual intercourse with their last new/temporary partner. Sexually active inconsistent condom users comprised 62% of the study population and contributed to 81% of the chlamydia infections. Asking whether a condom was used could quickly triage patients into groups with a ‘higher risk’ (none or inconsistent use of condoms and at least one new/temporary partners), and ‘lower risk’ (with more consistent condom use, although not always accurate) allowing for individualized care and counselling when screening for chlamydia. Evaluating whether a condom was used throughout the sexual intercourse did not add any useful information.

Comparing two definitions of ethnicity for identifying young persons at risk for chlamydia

Ethnic disparities in chlamydia infections in The Netherlands were assessed, in order to compare two definitions of ethnicity: ethnicity based on country of birth and self-defined ethnicity. Chlamydia positivity in persons aged 16-29 years was investigated using data from the first round of the Chlamydia Screening Implementation (CSI, 2008-2009) and surveillance data from STI centres (2009). Logistic regression modelling showed that being an immigrant was associated with chlamydia positivity in both CSI [adjusted odds ratio (aOR) 2·3, 95% confidence interval (CI) 2·0-2·6] and STI centres (aOR 1·4, 95% CI 1·3-1·5). In both settings, 60% of immigrants defined themselves as Dutch. Despite the difference, classification by self-defined ethnicity resulted in similar associations between (non-Dutch) ethnicity and chlamydia positivity. However, ethnicity based on country of birth explained variation in chlamydia positivity better, and is objective and constant over time and therefore more useful for identifying young persons at higher risk for chlamydia infection.

Chlamydia trachomatis infection during pregnancy associated with preterm delivery: a population-based prospective cohort study

Chlamydia trachomatis infection is the most prevalent bacterial sexually transmitted infection and may influence pregnancy outcome. This study was conducted to assess the effect of chlamydial infection during pregnancy on premature delivery and birthweight. Pregnant women attending a participating midwifery practice or antenatal clinic between February 2003 and January 2005 were eligible for the study. From 4,055 women self-administered questionnaires and urine samples, tested by PCR, were analysed for C. trachomatis infection. Pregnancy outcomes were obtained from midwives and hospital registries. Gestational ages and birthweights were analysed for 3,913 newborns. The C. trachomatis prevalence was 3.9%, but varied by age and socio-economic background. Chlamydial infection was, after adjustment for potential confounders, associated with preterm delivery before 32 weeks (OR 4.35 [95% CI 1.3, 15.2]) and 35 weeks gestation (OR 2.66 [95% CI 1.1, 6.5]), but not with low birthweight. Of all deliveries before 32 weeks and 35 weeks gestation 14.9% [95% CI 4.5, 39.5] and 7.4% [95% CI 2.5, 20.1] was attributable to C. trachomatis infection. Chlamydia trachomatis infection contributes significantly to early premature delivery and should be considered a public health problem, especially in young women and others at increased risk of C. trachomatis infection.

Rationale, design, and results of the first screening round of a comprehensive, register-based, Chlamydia screening implementation programme in the Netherlands

BACKGROUND

Implementing Chlamydia trachomatis screening in the Netherlands has been a point of debate for several years. The National Health Council advised against implementing nationwide screening until additional data collected from a pilot project in 2003 suggested that screening by risk profiles could be effective. A continuous increase in infections recorded in the national surveillance database affirmed the need for a more active approach. Here, we describe the rationale, design, and implementation of a Chlamydia screening demonstration programme.

METHODS

A systematic, selective, internet-based Chlamydia screening programme started in April 2008. Letters are sent annually to all 16 to 29-year-old residents of Amsterdam, Rotterdam, and selected municipalities of South Limburg. The letters invite sexually active persons to login to http://www.chlamydiatest.nl with a personal code and to request a test kit. In the lower prevalence area of South Limburg, test kits can only be requested if the internet-based risk assessment exceeds a predefined value.

RESULTS

We sent invitations to 261,025 people in the first round. One-fifth of the invitees requested a test kit, of whom 80% sent in a sample for testing. The overall positivity rate was 4.2%.

CONCLUSIONS

This programme advances Chlamydia control activities in the Netherlands. Insight into the feasibility, effectiveness, cost-effectiveness, and impact of this large-scale screening programme will determine whether the programme will be implemented nationally.

Evaluation design of a systematic, selective, internet-based, Chlamydia screening implementation in the Netherlands, 2008-2010: implications of first results for the analysis

BACKGROUND

A selective, systematic, Internet-based, Chlamydia Screening Implementation for 16 to 29-year-old residents started in three regions in the Netherlands in April 2008: in the cities of Amsterdam and Rotterdam and a more rural region, South Limburg. This paper describes the evaluation design and discusses the implications of the findings from the first screening round for the analysis. The evaluation aims to determine the effects of screening on the population prevalence of Chlamydia trachomatis after multiple screening rounds.

METHODS

A phased implementation or 'stepped wedge design' was applied by grouping neighbourhoods (hereafter: clusters) into three random, risk-stratified blocks (A, B and C) to allow for impact analyses over time and comparison of prevalences before and after one or two screening rounds. Repeated simulation of pre- and postscreening Chlamydia prevalences was used to predict the minimum detectable decline in prevalence. Real participation and positivity rates per region, block, and risk stratum (high, medium, and low community risk) from the 1st year of screening were used to substantiate predictions.

RESULTS

The results of the 1st year show an overall participation rate of 16% of 261,025 invitees and a positivity rate of 4.2%, with significant differences between regions and blocks. Prediction by simulation methods adjusted with the first-round results indicate that the effect of screening (minimal detectable difference in prevalence) may reach significance levels only if at least a 15% decrease in the Chlamydia positivity rate in the cities and a 25% decrease in the rural region after screening can be reached, and pre- and postscreening differences between blocks need to be larger.

CONCLUSIONS

With the current participation rates, the minimal detectable decline of Chlamydia prevalence may reach our defined significance levels at the regional level after the second screening round, but will probably not be significant between blocks of the stepped wedge design. Evaluation will also include other aspects and prediction models to obtain rational advice about future Chlamydia screening in the Netherlands.

Developing a system to predict laboratory-confirmed chlamydial and/or gonococcal urethritis in adult male emergency department patients

OBJECTIVES

We aimed to create a system for predicting which male emergency department (ED) patients with suspected chlamydial and/or gonococcal urethritis would have laboratory-confirmed infections based on clinical factors available at the initial ED encounter.

METHODS

We used statistical models to develop a system to predict either the presence or absence of laboratory-confirmed chlamydial and/or gonorrheal urethritis based on patient demographics and presenting symptoms. Data for the system were extracted from a retrospective chart review of adult male patients who were suspected of having, and were tested for, chlamydial and/or gonococcal urethritis at an adult, urban, northeastern United States, academic ED from January 1998 to December 2004.

RESULTS

Among the 822 patients tested, 29.2% had chlamydia, gonorrhea, or both infections; 13.8% were infected with chlamydia alone, 12.1% were infected with gonorrhea alone, and 3.3% were infected with both. From the statistical models, the following factors were predictive of a positive laboratory test for chlamydia and/or gonorrhea: age < or = 24 years, penile discharge, sexual contact with someone known to have chlamydia and/or gonorrhea, and not having health care insurance. A system using a hierarchical grouping of these factors based on the predicted probabilities of a laboratory-confirmed chlamydial and/or gonococcal urethritis, paired with baseline ED prevalence of these infections, was confirmed through internal validation testing to modestly predict which patients had or did not have a laboratory-confirmed infection.

CONCLUSIONS

This system of a combination of risk factors available during the clinical encounter in the ED modestly predicts which adult male patients suspected of having chlamydial and/or gonorrheal urethritis are more likely to have or not have a laboratory-confirmed infection. A prospective study is needed to create and validate a clinical prediction rule based on the results of this system.

Managing women with post-coital bleeding: a prospective observational non-comparative study

The management of post-coital bleeding (PCB) is inconsistent in the UK and there are no guidelines to ensure good practice. This prospective study was conducted to review the management and identify the diagnostic outcome of 137 women treated according to a locally devised protocol based on the best available evidence. Women underwent smear testing, taking triple swabs and colposcopy. The endometrium was investigated in postmenopausal women and in those aged >35 years with associated intermenstrual bleeding. Of those who had PCB for >4 weeks, only 8/124 (6.5%) were referred urgently. Twenty eight (20.4%) women were found to have significant pathology; 14 (50%) were <35 years of age, 26 (92.8%) had PCB for >4 weeks, whereas seven (25 %) suffered severe episodes, suggesting that the duration, but not age or severity, is relevant. A large multi-centre study is needed to provide more information in order to optimise the management.