J M Tobin

Incidence and reinfection rates of genital chlamydial infection among women aged 16–24 years attending general practice, family planning and genitourinary medicine clinics in England: a prospective cohort study by the Chlamydia Recall Study Advisory Group

Background: In England, screening for genital chlamydial infection has begun; however, screening frequency for women is not yet determined. Aim: To measure chlamydia incidence and reinfection rates among young women to suggest screening intervals. Methods: An 18-month prospective cohort study of women aged 16–24 years recruited from general practices, family planning clinics and genitourinary medicine (GUM) clinics: baseline-negative women followed for incidence and baseline-positive women for reinfection; urine tested every 6 months via nucleic acid amplification; and behavioural data collected. Extra test and questionnaire completed 3 months after initial positive test. Factors associated with infection and reinfection investigated using Cox regression stratified by healthcare setting of recruitment. Results: Chlamydia incidence was mean (95% CI) 4.9 (2.7 to 8.8) per 100 person-years (py) among women recruited from general practices, 6.4 (4.2 to 9.8) from family planning clinics and 10.6 (7.4 to 15.2) from GUM clinics. Incidence was associated with young age, history of chlamydial infection and acquisition of new sexual partners. If recently acquiring new partners, condom use at last sexual intercourse was independently associated with lower incidence. Chlamydia reinfection was mean (95% CI) 29.9 (19.7 to 45.4) per 100/person-year from general practices, 22.3 (15.6 to 31.8) from family planning clinics and 21.1 (14.3 to 30.9) from GUM clinics. Factors independently associated with higher reinfection rates were acquisition of new partners and failure to treat all partners. Conclusions: Sexual behaviours determined incidence and reinfection, regardless of healthcare setting. Our results suggest annual screening of women aged 16–24 years who are chlamydia negative, or sooner if partner change occurs. Rescreening chlamydia-positive women within 6 months of baseline infection may be sensible, especially if partner change occurs or all partners are not treated.

Opportunistic screening for genital chlamydial infection. II: prevalence among healthcare attenders, outcome, and evaluation of positive cases.

Objectives: To determine the prevalence and treatment outcomes among young women screened opportunistically for genital Chlamydia trachomatis and to evaluate the impact of screening in those participating. Design: An opportunistic screening programme (1 September 1999 to 31 August 2000) using urine samples, tested by ligase chain reaction (LCR). In-depth interviews were used for programme evaluation. Setting: Screening was offered in two health authorities at general practice, family planning, genitourinary medicine (GUM), adolescent sexual health, termination of pregnancy clinics and women’s services in hospitals (antenatal, colposcopy, gynaecology and infertility clinics). Main participants: Sexually active women (16–24 years) attending for any reason. Main outcome measures: Screening data: prevalence of infection by age and healthcare setting; proportion of positive patients attending for treatment. Evaluation data: participants’ attitudes and views towards screening and follow up. Results: In total, 16 930 women (16–24 years) were screened. Prevalence was higher in younger women (16–20) than those aged 21–24 years and was highly variable at different healthcare settings (range 3.4%–17.6%). Prevalence was approximately 9% in general practice. The role of the project health advisers in managing results and coordinating treatment of positive individuals was essential; the vast majority of all positives were known to be treated. Women felt that screening was beneficial. Improving awareness and education about sexually transmitted infections is required to alleviate negative reactions associated with testing positive for infection. Conclusions: Prevalence of infection outside GUM clinics is substantial and opportunistic screening using urine samples is an acceptable method of reaching individuals with infection who do not normally present at specialist clinics.

Relationship of cervical ectopy to chlamydia infection in young women

Objective Genital Chlamydia trachomatis infection is the most common bacterial sexually transmitted infection (STI) in the UK. Behaviours including multiple sex partners and inconsistent condom use, and biological factors such as cervical ectopy, may increase susceptibility to STIs. Cervical ectopy is thought to increase risk of chlamydia infection by exposing columnar epithelium to a potential infectious inoculum. This study aimed to determine whether chlamydia was more prevalent in young women with cervical ectopy. Methods Clinical notes of women aged 16–24 years attending the Portsmouth Genitourinary Medicine Clinic for an STI screen during the period May–July 2003 were reviewed retrospectively. Information collected included the presence or absence of cervical ectopy, smoking habits, methods of contraception, number of sexual partners in the previous 3 months, and previous STIs. Chlamydia infection was diagnosed by using strand displacement amplification on cervical swabs. Results A total of 231 women were included in the study. The mean age was 19.8 years. Evidence of cervical ectopy was found in 107 women. Chlamydial infection was detected in 37.4% (40/107) of those women with cervical ectopy and 21.8% (27/124) in those without cervical ectopy. This difference was statistically significant (p = 0.009). The significance remained even when accounting for confounding variables. Conclusions Cervical ectopy is a common physiological process in young women. Recognition of cervical ectopy should alert the clinician to the possibility of a genital chlamydia infection. Opportunistic screening for chlamydia in young people should be offered to reduce the prevalence of infection and its sequelae.

Using chlamydia positivity to estimate prevalence: evidence from the Chlamydia Screening Pilot in England

Studies have suggested that positivity can be used to estimate the prevalence of Chlamydia trachomatis in large-scale chlamydia screening programmes. A recent pilot of opportunistic screening in England estimated that the prevalence among 16–24-year-old women in Portsmouth and Wirral was 9.8% and 11.2%, respectively. This study assessed the continued validity of positivity as an approximate for prevalence. We re-analysed data from the Chlamydia Screening Pilot to estimate positivity, calculated as total positive tests divided by total tests, and compared these estimates with the previously reported prevalence, measured as the number of women testing positive divided by the total number of women screened. Overall positivity was 9.4% in Portsmouth and 11.0% in the Wirral; these estimates were not statistically different from prevalence, regardless of health-care setting, age group or symptoms. We conclude that positivity can be used as a proxy for prevalence.

Screening for genital chlamydia infection: DNA amplification techniques should be the test of choice

Our objective was to compare the sensitivities for the detection of Chlamydia trachomatis, of the ligase chain reaction (LCR) on first voided urine (FVU) specimens and enzyme immunoassay (EIA) on pooled endocervical/endourethral swabs from women and endourethral swabs from men. Men and women taking part in the UK chlamydia screening pilot were tested for chlamydia using LCR on a FVU. Patients attending genitourinary medicine clinics also had cervical and/or urethral swabs taken for chlamydia testing by EIA. In women, EIA on pooled swabs detected 575 of the 785 chlamydia positives and in men, EIA detected 209 of 351 positives. The sensitivity of EIA was 73% and 60% in women and men respectively. By using the EIA test, therefore, 27-40% of patients infected with chlamydia will be given a false negative result. We propose that it is unethical to use non-molecular testing in the future.

Opportunistic chlamydia screening; should positive patients be screened for co-infections?

This study examines the requirement for testing patients for other sexually transmitted infections (STIs) and bacterial vaginosis (BV) when diagnosed with genital chlamydia during opportunistic screening. Data were collected on all patients participating in the Department of Health chlamydia screening pilot study in Portsmouth. One thousand two hundred and forty-five women and 490 men with genital chlamydia were seen in Portsmouth genitourinary medicine (GUM) department. Of the women screened in GUM, 28% had coexisting STIs and 21% had BV. The corresponding figures for those initially screened in the community were 4% and 17%. An increased number of female sexual partners of male patients (76%) and male partners of female patients (55%) of the GUM group had co-infections; 58% of male partners from the community group had another STI. The increased morbidity associated with these infections warrants screening of all patients with chlamydia for other STIs and BV.

Who has chlamydia? The prevalence of genital tract Chlamydia trachomatis within Portsmouth and South East Hampshire, UK

Objective To determine the prevalence of genital tract Chlamydia trachomatis infection in women and men attending different health care settings in Portsmouth and South East Hampshire. Design Prospective, opportunistic screening. Setting Multiple health care sites. Participants Consenting sexually active women and men. Intervention A urine sample was tested for Chlamydia trachomatis and positive patients were offered treatment and partner notification. Main outcome measures The presence or absence of chlamydia infection according to age, gender, health care setting and reason for attendance. Results A total of 14 756 samples were tested giving an overall prevalence of 9.6%. The prevalence was significantly higher in women attending for a termination of pregnancy, antenatal care, women and men attending genitourinary medicine and in those with genital tract symptoms. The prevalence was different for men and women at different ages. Conclusion The prevalence of genital Chlamydia trachomatis infection was high but differed at various health care settings and by reason for attendance.

Which treatment for genital tract Chlamydia trachomatis infection

A national opportunistic chlamydia screening programme, mainly targeting young sexually active women, is gradually being introduced across the UK and in future will predominantly occur in primary care sites. The relative efficacy of recommended antibiotic treatments for chlamydia has been poorly studied and especially that of single dose azithromycin. In Portsmouth, 1536 patients treated for chlamydia, with four different antibiotic regimens, during the Department of Health pilot study, were asked to return for test of cure. No difference in treatment outcome was found using doxycycline, oxytetracycline, erythromycin or azithromycin. Directly observed therapy with azithromycin may be especially helpful in treating young chlamydia-positive patients.

Attendance by older patients at a genitourinary medicine clinic

Objectives: To determine how patients aged 50 and above had been referred to a department of genitourinary medicine (GUM), why they had attended, their sexual histories, and what diagnoses were made. To identify any special sexual health needs in this group of patients. Methods: A case note review was undertaken of all patients aged 50 and over attending the Portsmouth GUM department over a 3 month period. Results: There was a marked difference in reason for attendance between men and women in this older age group. Men were more likely to attend for a sexual health screen, often with minimal or no symptoms, following an extramarital or casual liaison. Women more commonly had symptoms causing difficulties with sexual intercourse with their regular partner. Conclusions: Older people present to GUM departments with a wide range of sexually associated problems. The diagnostic and management expertise available in GUM departments makes them ideal providers of sexual health care for this as well as younger age groups.

Re-infection of Chlamydia trachomatis in patients presenting to the genitourinary medicine clinic in Portsmouth: the chlamydia screening pilot study — three years on

Chlamydia trachomatis is the most common bacterial sexually transmitted infection (STI) in the UK. The Department of Health set up an opportunistic screening programme for genital chlamydia infection, focusing on sexually active 16–24-year-old women and some men. This study identified those patients re-attending the genitourinary medicine (GUM) clinic and followed them up until September 2002. We examined the reasons for attendance and re-infection with chlamydia. Two hundred and eighty-five patients re-attended the clinic. Two-thirds of these had changed their sexual partners in the follow-up period. Fifty-six patients were diagnosed with genital chlamydia infection in subsequent clinic visits. The majority of them had changed their sexual partners, suggesting new acquisition of infection. This suggests that in this age group re-screening should be offered at a year interval. Patients diagnosed with genital chlamydia infection should be referred to the GUM clinic for further STI screening and partner notification.