What can be gained from comprehensive disaggregate surveillance? The Avon Surveillance System for Sexually Transmitted Infections

Cross-sectional study to evaluate Trichomonas vaginalis positivity in women tested for Neisseria gonorrhoeae and Chlamydia trachomatis, attending genitourinary medicine and primary care clinics in Bristol, South West England

BACKGROUND

Highly sensitive, commercial nucleic acid amplification tests (NAAT) for Trichomonas vaginalis have only recently been recommended for use in the UK. While testing for T. vaginalis is routine in symptomatic women attending genitourinary medicine (GUM) clinics, it is rare in asymptomatic women or those attending primary care. The aim of this study was to evaluate the positivity of T. vaginalis using a commercial NAAT, in symptomatic and asymptomatic women undergoing testing for chlamydia and gonorrhoea in GUM and primary care settings.

METHODS

Samples from 9186 women undergoing chlamydia and gonorrhoea testing in South West England between May 2013 and Jan 2015 were also tested for T. vaginalis by NAAT alongside existing tests.

RESULTS

T. vaginalis positivity using NAAT was as follows: in GUM 4.5% (24/530, symptomatic) and 1.7% (27/1584, asymptomatic); in primary care 2.7% (94/3499, symptomatic) and 1.2% (41/3573, asymptomatic). Multivariable regression found that in GUM older age, black ethnicity and deprivation were independent risk factors for T. vaginalis infection. Older age and deprivation were also risk factors in primary care. Testing women presenting with symptoms in GUM and primary care using TV NAATs is estimated to cost £260 per positive case diagnosed compared with £716 using current microbiological tests.

CONCLUSIONS

Aptima TV outperforms existing testing methods used to identify T. vaginalis infection in this population. An NAAT should be used when testing for T. vaginalis in women who present for testing with symptoms in primary care and GUM, based on test performance and cost.

Patterns of chlamydia testing in different settings and implications for wider STI diagnosis and care: a probability sample survey of the British population

Background

Following widespread rollout of chlamydia testing to non-specialist and community settings in the UK, many individuals receive a chlamydia test without being offered comprehensive STI and HIV testing. We assess sexual behaviour among testers in different settings with a view to understanding their need for other STI diagnostic services.

Methods

A probability sample survey of the British population undertaken 2010–2012 (the third National Survey of Sexual Attitudes and Lifestyles). We analysed weighted data on chlamydia testing (past year), including location of most recent test, and diagnoses (past 5 years) from individuals aged 16–44 years reporting at least one sexual partner in the past year (4992 women, 3406 men).

Results

Of the 26.8% (95% CI 25.4% to 28.2%) of women and 16.7% (15.5% to 18.1%) of men reporting a chlamydia test in the past year, 28.4% of women and 41.2% of men had tested in genitourinary medicine (GUM), 41.1% and 20.7% of women and men respectively tested in general practice (GP) and the remainder tested in other non-GUM settings. Women tested outside GUM were more likely to be older, in a relationship and to live in rural areas. Individuals tested outside GUM reported fewer risk behaviours; nevertheless, 11.0% (8.6% to 14.1%) of women and 6.8% (3.9% to 11.6%) of men tested in GP and 13.2% (10.2% to 16.8%) and 9.6% (6.5% to 13.8%) of women and men tested in other non-GUM settings reported ‘unsafe sex’, defined as two or more partners and no condom use with any partner in the past year. Individuals treated for chlamydia outside GUM in the past 5 years were less likely to report an HIV test in that time frame (women: 54.5% (42.7% to 65.7%) vs 74.1% (65.9% to 80.9%) in GUM; men: 23.9% (12.7% to 40.5%) vs 65.8% (56.2% to 74.3%)).

Conclusions

Most chlamydia testing occurred in non-GUM settings, among populations reporting fewer risk behaviours. However, there is a need to provide pathways to comprehensive STI care to the sizeable minority at higher risk.

The added value of chlamydia screening between 2008-2010 in reaching young people in addition to chlamydia testing in regular care; an observational study

Background

Internet-based Chlamydia Screening Implementation (chlamydia screening programme) was introduced in the Netherlands in 2008-2010 to detect and treat asymptomatic infections and to limit ongoing transmission through annual testing and treatment of Chlamydia trachomatis in young people (16-29 years). This population-based screening may be less effective when addressing individuals who are already covered by regular care, instead of addressing a hidden key population without chlamydia testing experience in regular care. This study had two aims: (1) to assess the rate and determinants of newly reached (i.e. not previously tested in 2006-2010) participants in the chlamydia screening programme, and (2) to assess the chlamydia positivity in these newly reached participants.

Methods

This observational matching study included all chlamydia tests performed in subjects aged 16-29 years in eastern South Limburg in the Netherlands (population 16-29 years:41,000) between 2006-2010. Testing was conducted during the systematic chlamydia screening programme (2008-2010), at a sexually transmitted infections clinic (STI clinic), by general practitioners (GPs), and by medical specialists as reported by the medical laboratory serving the region. Data were matched between testing services on individual level. The study population included all participants who were tested at least once for chlamydia by the chlamydia screening programme. Participants were included at their first chlamydia screening participation.

Results

In the chlamydia screening programme, 80.7% (4298/5323) of participants were newly reached, others were previously tested by the STI clinic (5.7%, n=304), GPs (6.2%, n=328), medical specialists (3.5%, n=187) or a combination of providers (3.9%, n=206). Chlamydia prevalence was similar in newly reached participants (4.8%, 204/4298) and participants previously tested (4.5%, 46/1025, P=0.82). Independent determinants for being a newly reached participant were male gender (men OR 2.9; 95% CI 2.5-3.4) and young age <21 years (versus 25-29 years OR 1.8; 95% CI 1.5-2.2).

Conclusions

The majority of the chlamydia screening programme participants have not been tested by regular care, and show similar chlamydia prevalence as those previously tested. Thereby population-based chlamydia screening adds to the existing regular care by testing young individuals hidden to current regular care.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0612-2) contains supplementary material, which is available to authorized users.

Analysis of laboratory testing results collected in an enhanced chlamydia surveillance system in Australia, 2008-2010

BACKGROUND

Chlamydial infection is the most common notifiable disease in Australia, Europe and the US. Australian notifications of chlamydia rose four-fold from 20,274 cases in 2002 to 80,846 cases in 2011; the majority of cases were among young people aged less than 29 years. Along with test positivity rates, an understanding of the number of tests performed and the demographics of individuals being tested are key epidemiological indicators. The ACCESS Laboratory Network was established in 2008 to address this issue.

METHODS

The ACCESS Laboratory Network collected chlamydia testing data from 15 laboratories around Australia over a three-year period using data extraction software. All chlamydia testing data from participating laboratories were extracted from the laboratory information system; patient identifiers converted to a unique, non-reversible code and de-identified data sent to a single database. Analysis of data by anatomical site included all specimens, but in age and sex specific analysis, only one testing episode was counted.

RESULTS

From 2008 to 2010 a total of 628,295 chlamydia tests were referred to the 15 laboratories. Of the 592,626 individual episodes presenting for testing, 70% were from female and 30% from male patients. In female patients, chlamydia positivity rate was 6.4% overall; the highest rate in 14 year olds (14.3%). In male patients, the chlamydia positivity rate was 9.4% overall; the highest in 19 year olds (16.5%). The most common sample type was urine (57%). In 3.2% of testing episodes, multiple anatomical sites were sampled. Urethral swabs gave the highest positivity rate for all anatomical sites in both female (7.7%) and male patients (14%), followed by urine (7.6% and 9.4%, respectively) and eye (6.3% and 7.9%, respectively).

CONCLUSIONS

The ACCESS Laboratory Network data are unique in both number and scope and are representative of chlamydia testing in both general practice and high-risk clinics. The findings from these data highlight much lower levels of testing in young people aged 20 years or less; in particular female patients aged less than 16 years, despite being the group with the highest positivity rate. Strategies are needed to increase the uptake of testing in this high-risk group.

Not so different after all? Comparing patients attending general practice-based locally enhanced services for sexual health with patients attending genitourinary medicine

We did a cross-sectional survey of patients attending genitourinary (GU) medicine clinics (n = 933) and general practice-based Locally Enhanced Services for Sexual Health (GP-LESSH, n = 111) in Cornwall, England, in 2009/2010, to compare patients' characteristics and experiences. Patients completed a pen-and-paper questionnaire that was then linked to an extract of their clinical data. GP-LESSH patients took longer both to seek and to receive care: medians of nine and seven days, respectively, versus GU medicine patients: medians of seven and one day, respectively. GP-LESSH patients were less likely than GU medicine patients to report symptoms (19.6% versus 30.6%) and sexual risk behaviours (33.3% versus 44.7% reported new partners) since recognizing needing to seek care; 5.0% versus 10.2% were men who have sex with men). However, they were equally likely to have sexually transmitted infections (STIs) diagnosed (23.3% versus 24.8%). As GP-LESSH may operate infrequently, local services must work collaboratively to ensure that those seeking care for suspected STIs receive it promptly. Failing to do so facilitates avoidable STI transmission.

Trends in testing and notification for genital gonorrhoea in a northern Australian district, 2004 - 2008

Background The study aimed to examine the trends in notification and testing for genital gonorrhoea (Neisseria gonorrhoeae) in the Darwin Remote District of Northern Territory, Australia, between 2004 and 2008. Methods: Using laboratory testing data and notification data, we calculated the annual sex- and age-specific notification rates, testing rates and positivity rates, and examined their trends. A deterministic matching method was used to identify unique individuals tested in order to estimate the number of years out of five in which each individual was tested. The correlation between testing rates and notification rates was calculated. Results: The notification rates for the 15–24 year age group increased sharply from 2004 to 2005, and then trended downwards between 2005 and 2008, with a decrease of 48.2% in females and 59.9% in males. No evident trends were found in testing rates. The positivity rates for this age group decreased by 46.3% in females (from 8.9% to 4.8%), and by 70.4% in males (from 10.8% to 3.2%) between 2004 and 2008. Over 76% of the population in this age-group had been tested at least once during the study period. A moderate correlation was found between notification rates and testing rates in both sexes. Conclusions: There was a significant decreasing trend in the notification rate of gonorrhoea between 2005 and 2008, which was most probably due to a decrease in prevalence. This study demonstrates the importance and utility of population-level testing data in understanding the epidemiology of common bacterial sexually transmissible infections such as gonorrhoea.

Establishing a linked sentinel surveillance system for blood-borne viruses and sexually transmissible infections: methods, system attributes and early findings

OBJECTIVE

To describe the attributes and key findings from implementation of a new blood-borne virus (BBV) and sexually transmissible infection (STI) sentinel surveillance system based on routine testing at clinical sites in Victoria, Australia.

METHODS

The Victorian Primary Care Network for Sentinel Surveillance (VPCNSS) on BBV and STI was established in 2006 at 17 sites. Target populations included men who have sex with men (MSM), young people and injecting drug users (IDU). Sites collected demographic and risk behaviour information electronically or using paper surveys from patients undergoing routine HIV or STI (syphilis, chlamydia (Chlamydia trachomatis)) or hepatitis C virus (HCV) testing. These data were linked with laboratory results.

RESULTS

Between April 2006 and June 2008, data were received for 67 466 tests and 52 042 questionnaires. In clinics providing electronic data, >90% of individuals tested for HIV, syphilis and chlamydia had risk behaviour information collected. In other clinics, survey response rates were >85% (HIV), 43.5% (syphilis), 42.7-66.5% (chlamydia) and <20% (HCV). Data completeness was >85% for most core variables. Over time, HIV, syphilis and chlamydia testing increased in MSM, and chlamydia testing declined in females (P = 0.05). The proportion of positive tests among MSM was 1.9% for HIV and 2.1% for syphilis. Among 16-24-year-olds, the proportion positive for chlamydia was 10.7% in males and 6.9% in females. Among IDU, 19.4% of HCV tests were antibody positive.

CONCLUSIONS

The VPCNSS has collected a large, rich dataset through which testing, risk behaviours and the proportion positive can be monitored in high-risk groups, offering a more comprehensive BBV and STI surveillance system for Victoria. Building system sustainability requires an ongoing focus.

Surveillance of community genital Chlamydia trachomatis testing in the East of England, 2008-2010

BACKGROUND

Widespread testing for chlamydia is expected to result in a reduction in prevalence. In 2008, coverage indicators introduced by the Department of Health (DH) required collection and submission of all tests performed outside of genitourinary medicine clinics. No mechanism existed to collect community-based tests conducted outside of the National Chlamydia Screening Programme. The Health Protection Agency Regional Epidemiology Unit in the East of England (EoE) set up a new system to routinely collect and submit these tests on behalf of the regional Primary Care Organizations (PCOs).

METHODS

Testing data were requested from all laboratories commissioned to undertake chlamydia testing by EoE PCOs. Data were imported into a bespoke Structured Query Language server database and automated data processing routines were run. Data fulfilling national criteria were submitted for inclusion in the DH indicators.

RESULTS

High-quality data were submitted to set deadlines with minimum impact on laboratories. Completeness of data variables varied by laboratory and by variable type. After complex data processing, 96% of laboratory reported tests in the 15-24 year age range were eligible for submission.

CONCLUSIONS

This centralized method of data collection provides high-quality data, allowing for further analysis, which can be used to inform improvements in health care. These methods could be transferred to any of the hundreds of organisms for which similar laboratory data exist.

Testing for sexually transmitted infections in general practice: cross-sectional study

Background

Primary care is an important provider of sexual health care in England. We sought to explore the extent of testing for chlamydia and HIV in general practice and its relation to associated measures of sexual health in two contrasting geographical settings.

Methods

We analysed chlamydia and HIV testing data from 64 general practices and one genitourinary medicine (GUM) clinic in Brent (from mid-2003 to mid-2006) and 143 general practices and two GUM clinics in Avon (2004). We examined associations between practice testing status, practice characteristics and hypothesised markers of population need (area level teenage conception rates and Index of Multiple Deprivation, IMD scores).

Results

No HIV or chlamydia testing was done in 19% (12/64) of general practices in Brent, compared to 2.1% (3/143) in Avon. In Brent, the mean age of general practitioners (GPs) in Brent practices that tested for chlamydia or HIV was lower than in those that had not conducted testing. Practices where no HIV testing was done had slightly higher local teenage conception rates (median 23.5 vs. 17.4/1000 women aged 15-44, p = 0.07) and served more deprived areas (median IMD score 27.1 vs. 21.8, p = 0.05). Mean yearly chlamydia and HIV testing rates, in practices that did test were 33.2 and 0.6 (per 1000 patients aged 15-44 years) in Brent, and 34.1 and 10.3 in Avon, respectively. In Brent practices only 20% of chlamydia tests were conducted in patients aged under 25 years, compared with 39% in Avon.

Conclusions

There are substantial geographical differences in the intensity of chlamydia and HIV testing in general practice. Interventions to facilitate sexually transmitted infection and HIV testing in general practice are needed to improve access to effective sexual health care. The use of routinely-collected laboratory, practice-level and demographic data for monitoring sexual health service provision and informing service planning should be more widely evaluated.

Are primary care-based sexually transmitted infection services in the UK delivering public health benefit?

Sexual health services in primary care, known in the UK as local enhanced services in sexual health (LESSH), aim to increase access to sexually transmitted infection (STI) screening and treatment. Little is known about the characteristics, quality or public health impact of these services. We identified national standards for service provision, and evaluated LESSH against them using a structure, process and outcome approach. Clinical structure and process standards were generally well met, with the exception of partner notification provision. However, public health and outcome measures were largely unascertainable and often undefined in the standards. If the primary care STI services are to deliver public health benefit, improved outcome measures and data collection are required.

Use of a primary care database to determine trends in genital chlamydia testing, diagnostic episodes and management in UK general practice, 1990-2004

OBJECTIVE

To determine the extent of testing, diagnostic episodes and management of genital Chlamydia trachomatis (CT) infection in UK primary care using a large primary care database.

METHODS

The incidence of CT tests, diagnostic episodes, treatments and referrals was measured for all adult patients in the General Practice Research Database between 1990 and 2004.

RESULTS

Rates of CT testing in those aged 12-64 years in 2004 increased to 1439/100,000 patient years (py) in women but only 74/100,000 py in men. Testing rates were highest among 20-24-year-old women (5.5% tested in 2004), followed by 25-34-year-old women (3.7% tested in 2004). 0.5% of registered 16-24-year-old women were diagnosed as having CT infection in 2004. Three-quarters of patients with a recorded diagnosis of CT had had an appropriate prescription issued in 2004, a proportion that increased from 1990 along with a decrease in referrals to genitourinary medicine. In 2004, general practitioners treated 25.0% of all recorded diagnoses of CT in women and 5.1% of those in men.

CONCLUSIONS

Testing for and diagnostic episodes of CT in primary care have increased since 1990. Testing continues disproportionately to target women aged >24 years. Extremely low rates of testing in men, together with high positivity, demonstrate a missed opportunity for diagnosis of CT and contact tracing in general practice.