Screening for Chlamydia trachomatis: a systematic review of the economic evaluations and modelling

Evaluation of Chlamydia trachomatis screening from the perspective of health economics: a systematic review

Background

Most Chlamydia trachomatis (CT) infections are asymptomatic. The infection can persist and lead to severe sequelae. Therefore, screening for CT can primarily prevent serious sequelae.

Aim

To systematically evaluate CT screening from the perspective of health economics, summarize previous findings from different target populations, and make practical recommendations for developing local CT screening strategies.

Methods

PubMed, Web of Science, Embase, Cochran Library, and National Health Service Economic Evaluation Database (Ovid) were searched from January 1, 2000, to March 4, 2023. Studies reporting the cost-effectiveness, cost-benefit, or cost-utility of CT screening were eligible to be included. A narrative synthesis was used to analyze and report the results following the PRISMA guidelines. The Consensus on Health Economic Criteria (CHEC) list was used to assess the methodological quality of included studies.

Results

Our review finally comprised 39 studies addressing four populations: general sexually active people (n = 25), pregnant women (n = 4), women attending STD and abortion clinics (n = 4), and other high-risk individuals (n = 6). The total number of participants was ~7,991,198. The majority of studies assessed the cost-effectiveness or cost-utility of the screening method. The results showed that the following screening strategies may be cost-effective or cost-saving under certain conditions: performing CT screening in young people aged 15-24 in the general population, military recruits, and high school students; incorporating CT screening into routine antenatal care for pregnant women aged 15-30; opportunistic CT screening for women attending STD and abortion clinics; home-obtained sampling for CT screening using urine specimens or vaginal swab; performing CT screening for 14-30-year-old people who enter correctional institutions (i.e., jail, detention) as soon as possible; providing CT screening for female sex workers (FSWs) based on local incidence and prevalence; adding routine CT screening to HIV treatment using rectal samples from men who have sex with men (MSM).

Conclusion

We found that CT screening in general sexually active people aged 15-24, military recruits, high school students, pregnant women aged 15-30, women attending STD and abortion clinics, people entering jail, detention, FSWs, and MSM has health economic value. Due to the different prevalence of CT, diversities of economic conditions, and varying screening costs among different populations and different countries, regions, or settings, no uniform and standard screening strategies are currently available. Therefore, each country should consider its local condition and the results of health economic evaluations of CT screening programs in that country to develop appropriate CT screening strategies.

Costs, Health Benefits, and Cost-Effectiveness of Chlamydia Screening and Partner Notification in the United States, 2000-2019: A Mathematical Modeling Analysis

BACKGROUND

Chlamydia remains a significant public health problem that contributes to adverse reproductive health outcomes. In the United States, sexually active women 24 years and younger are recommended to receive annual screening for chlamydia. In this study, we evaluated the impact of estimated current levels of screening and partner notification (PN), and the impact of screening based on guidelines on chlamydia associated sequelae, quality adjusted life years (QALYs) lost and costs.

METHODS

We conducted a cost-effectiveness analysis of chlamydia screening, using a published calibrated pair formation transmission model that estimated trends in chlamydia screening coverage in the United States from 2000 to 2015 consistent with epidemiological data. We used probability trees to translate chlamydial infection outcomes into estimated numbers of chlamydia-associated sequelae, QALYs lost, and health care services costs (in 2020 US dollars). We evaluated the costs and population health benefits of screening and PN in the United States for 2000 to 2015, as compared with no screening and no PN. We also estimated the additional benefits that could be achieved by increasing screening coverage to the levels indicated by the policy recommendations for 2016 to 2019, compared with screening coverage achieved by 2015.

RESULTS

Screening and PN from 2000 to 2015 were estimated to have averted 1.3 million (95% uncertainty interval [UI] 490,000-2.3 million) cases of pelvic inflammatory disease, 430,000 (95% UI, 160,000-760,000) cases of chronic pelvic pain, 300,000 (95% UI, 104,000-570,000) cases of tubal factor infertility, and 140,000 (95% UI, 47,000-260,000) cases of ectopic pregnancy in women. We estimated that chlamydia screening and PN cost $9700 per QALY gained compared with no screening and no PN. We estimated the full realization of chlamydia screening guidelines for 2016 to 2019 to cost $30,000 per QALY gained, compared with a scenario in which chlamydia screening coverage was maintained at 2015 levels.

DISCUSSION

Chlamydia screening and PN as implemented in the United States from 2000 through 2015 has substantially improved population health and provided good value for money when considering associated health care services costs. Further population health gains are attainable by increasing screening further, at reasonable cost per QALY gained.

Financing care for Severe Stigmatizing Skin Diseases (SSSDs) in Liberia: challenges and opportunities

Introduction

Neglected tropical diseases (NTDs) are an important global health challenge, however, little is known about how to effectively finance NTD related services. Integrated management in particular, is put forward as an efficient and effective treatment modality. This is a background study to a broader health economic evaluation, seeking to document the costs of integrated case management of NTDs versus standard care in Liberia. In the current study, we document barriers and facilitators to NTD care from a health financing perspective.

Methods

We carried out key informant interviews with 86 health professionals and 16 national health system policymakers. 46 participants were active in counties implementing integrated case management and 40 participants were active in counties implementing standard care. We also interviewed 16 patients and community members. All interviews were transcribed and analysed using the thematic framework approach.

Findings

We found that decentralization for NTD financing is not yet achieved – financing and reporting for NTDs is still centralized and largely donor-driven as a vertical programme; government involvement in NTD financing is still minimal, focused mainly on staffing, but non-governmental organisations (NGOs) or international agencies are supporting supply and procurement of medications. Donor support and involvement in NTDs are largely coordinated around the integrated case management. Quantification for goods and budget estimations are specific challenges, given the high donor dependence, particularly for NTD related costs and the government’s limited financial role at present. These challenges contribute to stockouts of medications and supplies at clinic level, while delays in payments of salaries from the government compromise staff attendance and retention. For patients, the main challenges are high transportation costs, with inflated charges due to fear and stigma amongst motorbike taxi riders, and out-of-pocket payments for medication during stockouts and food/toiletries (for in-patients).

Conclusion

Our findings contribute to the limited work on financing of SSSD services in West African settings and provide insight on challenges and opportunities for financing and large costs in accessing care by households, which is also being exacerbated by stigma.

Evaluation of the Predictive Value of Urine Leukocyte Esterase Test in Chlamydia trachomatis and Neisseria gonorrhoeae Infection Among Males Attending HIV/STI Clinics in Guangdong Province, China

Leukocyte esterase test (LET) detection is a simple and inexpensive test performed by urinalysis. This study investigated the predictive value of LET for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infection among men attending HIV and sexually transmitted infection (HIV/STI) clinics in Guangdong Province, China. A total of 5,509 urine samples were collected from HIV and sexually transmitted infection clinics in Guangdong Province between 2017 and 2019. Specimens from 5,464 males were tested by both LET and nucleic acid amplification test (NAAT). Of 5,464 males, 497 (9.1%) tested positive for CT or NG by NAAT, with respective prevalence rates of 6.4% (95% confidence interval [95% CI]: 5.8-7.1%) and 3.8% (95% CI: 3.3-4.3%), including 1.2% (95% CI: 0.9-1.4%) co-infected. Compared to the HIV-negative individuals, individuals living with HIV tend to have a higher prevalence of CT, NG and co-infection with CT and NG. The LET sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for CT were 46.4% (95% CI: 41.2-51.7%), 92.0% (95% CI: 91.2-92.7%), 28.4% (95% CI: 24.8-32.1%), and 96.1% (95% CI: 95.6-96.7%), respectively. The LET sensitivity, specificity, PPV, and NPV for NG were 68.4% (95% CI: 62.1-74.7%), 91.8% (95% CI: 91.1-92.6%), 25.0% (95% CI: 21.4-28.5%), and 98.7% (95% CI: 98.3-99%), respectively. Compared to the HIV-negative individuals, higher sensitivity and specificity were observed for HIV-positive individuals, but there was no statistical difference. The incremental cost-effectiveness ratio (ICER) using economic costs per additional person CT positive and NG positive was -$238.74 and -$145.60 compared with LET positive, respectively. LET is a cost-effective test and will be valuable for predicting CT and NG infection, which is highly prevalent in low- and middle-income countries.

What is the effectiveness of community-based health promotion campaigns on chlamydia screening uptake in young people and what barriers and facilitators have been identified? A mixed-methods systematic review

BACKGROUND

The UK National Chlamydia Screening Programme uses an opportunistic approach. Many programmes use campaigns to raise awareness of chlamydia screening in young people. This review aimed to assess the effectiveness of campaigns on uptake of chlamydia screening in young people.

METHODS

We conducted a mixed-methods systematic review of articles assessing the outcomes of community-based health-promotion campaigns to increase chlamydia screening in young people, their experiences of the campaigns and other facilitators and barriers to the conduct of the campaigns. We searched four databases for quantitative and qualitative studies with no language restrictions.

MAIN RESULTS

From 10 329 records identified, 19 studies (20 articles) were included in the review: 14 quantitative, 2 qualitative and 3 mixed methods. All studies with quantitative outcomes were before-after study designs or interrupted time series. The prediction interval for relative change (RC) in test counts ranged from 0.95 to 1.56, with a summary pooled estimate of RC 1.22 (95% CI 1.14 to 1.30, 13 studies, I²=97%). For test positivity rate, 95% prediction interval was 0.59 to 1.48, with a summary pooled estimate of RC 0.93 (95% CI 0.81 to 1.07, 8 studies, I²=91.8%). Large variation in characteristics between studies precluded exploring outcomes by type of campaign components. Seven major qualitative themes to improve screening were identified: targeting of campaigns; quality of materials and message; language; anonymity; use of technology; relevance; and variety of testing options.

CONCLUSIONS

Health promotion campaigns aiming to increase chlamydia testing in those aged 15-24 years may show some effectiveness in increasing overall numbers of tests, however numbers of positive tests do not follow the same trend. Qualitative findings indicate that campaigns require clear, relevant messaging that displays the full range of testing options and assures anonymity in order to be effective.

Assessing the costs and outcomes of control programmes for sexually transmitted infections: a systematic review of economic evaluations

OBJECTIVE

To identify economic evaluations of interventions to control STIs and HIV targeting young people, and to assess how costs and outcomes are measured in these studies.

DESIGN

Systematic review.

DATA SOURCES

Seven databases were searched (Medline (Ovid), EMBASE (Ovid), Web of Science, PsycINFO, NHS Economic Evaluation Database, NHS Health Technology Assessment and Database of Abstracts of Reviews of Effects) from January 1999 to April 2019. Key search terms were STIs (chlamydia, gonorrhoea, syphilis) and HIV, cost benefit, cost utility, economic evaluation, public health, screening, testing and control.

REVIEW METHODS

Studies were included that measured costs and outcomes to inform an economic evaluation of any programme to control STIs and HIV targeting individuals predominantly below 30 years of age at risk of, or affected by, one or multiple STIs and/or HIV in Organisation for Economic Co-operation and Development countries. Data were extracted and tabulated and included study results and characteristics of economic evaluations. Study quality was assessed using the Philips and BMJ checklists. Results were synthesised narratively.

RESULTS

9530 records were screened and categorised. Of these, 31 were included for data extraction and critical appraisal. The majority of studies assessed the cost-effectiveness or cost-utility of screening interventions for chlamydia from a provider perspective. The main outcome measures were major outcomes averted and quality-adjusted life years. Studies evaluated direct medical costs, for example, programme costs and 11 included indirect costs, such as productivity losses. The study designs were predominantly model-based with significant heterogeneity between the models.

DISCUSSION/CONCLUSION

None of the economic evaluations encompassed aspects of equity or context, which are highly relevant to sexual health decision-makers. The review demonstrated heterogeneity in approaches to evaluate costs and outcomes for STI/HIV control programmes. The low quality of available studies along with the limited focus, that is, almost all studies relate to chlamydia, highlight the need for high-quality economic evaluations to inform the commissioning of sexual health services.

Methods and quality of disease models incorporating more than two sexually transmitted infections: a protocol for a systematic review of the evidence

INTRODUCTION

Disease models can be useful tools for policy makers to inform their decisions. They can help to estimate the costs and benefits of interventions without conducting clinical trials and help to extrapolate the findings of clinical trials to a population level.Sexually transmitted infections (STIs) do not operate in isolation. Risk-taking behaviours and biological interactions can increase the likelihood of an individual being coinfected with more than one STI.Currently, few STI models consider coinfection or the interaction between STIs. We aim to identify and summarise STI models for two or more STIs and describe their modelling approaches.

METHODS AND ANALYSIS

Six databases (Cochrane, Embase, PLOS, ProQuest, Medline and Web of Science) were searched on 27 November 2018 to identify studies that focus on the reporting of the methodology and quality of models for at least two different STIs. The quality of all eligible studies will be accessed using a percentage scale published by Kopec et al . We will summarise all used approaches to model two or more STIs in one model. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework will be used to report all outcomes.

ETHICS AND DISSEMINATION

Ethical approval is not required for this systematic review. The results of this review will be published in a peer-reviewed journal and presented at a suitable conference. The findings from this review will be used to inform the development of a new multi-STI model.

PROSPERO REGISTRATION NUMBER

CRD42017076837.

Dynamic transmission models for economic analysis applied to health care-associated infections: A review of the literature

BACKGROUND

Cost-effectiveness analyses are an important methodology in assessing whether a health care technology is suitable for widespread adoption. Common models used by economists, such as decision trees and Markov models, are appropriate for noninfectious diseases where treatment and exposure are independent. Diseases whose treatment and exposure are dependent require dynamic models to incorporate the nonlinear transmission effect. Two different types of models are often used for dynamic cost-effectiveness analyses: compartmental models and individual models. In this methodology-focused literature review, we describe each model type and summarize the literature associated with each using the example of health care-associated infections (HAIs).

METHODS

We conducted a review of the literature to identify dynamic cost-effectiveness analyses that examined interventions to prevent or treat HAIs. To be included in the review, studies needed to have each of 3 necessary components: involve economics, such as cost-effectiveness analysis and evidence of economic theory, use a dynamic transmission model, and examine HAIs.

RESULTS

Of the 9 articles published between 2005 and 2016 that met criteria to be included in our study, 3 used compartmental models and 6 used individual models.

CONCLUSIONS

Very few published studies exist that use dynamic transmission models to conduct economic analyses related to HAIs and even fewer studies have used these models to perform cost-effectiveness analyses.

A Systematic Review of the Techniques Used to Value Temporary Health States

BACKGROUND

A broad literature on health state utility values exists, but compared with chronic health states (HSs), issues surrounding the valuation of temporary health states (THSs) have been poorly explored.

OBJECTIVES

To assess the methods used by previous studies to value HSs that are considered temporary so as to determine the strengths and limitations associated with various approaches and to inform future study designs.

METHODS

A systematic review was undertaken to explore the methods used, assess how the valuation was conducted for diseases that might lead to HSs deemed as temporary, and identify the challenges encountered in the valuation of THSs.

RESULTS

Of the 36 relevant studies, 22 were explicit that the HS being valued was temporary. Most of the studies used more than one technique (often incorporating both conventional and adapted approaches). In using adapted techniques, the primary challenge was identifying an appropriate intermediate "anchor" HS and the possibility of negative utilities.

CONCLUSIONS

There is no agreement on the most methodologically robust approach to THS valuation. Valuation is complex and important issues relating to the validity, practicality, and reliability of the techniques used were not adequately covered by most of the studies identified.

Cost-effectiveness of microscopy of urethral smears for asymptomatic Mycoplasma genitalium urethritis in men in England

The objective was to determine whether or not the limited use of urethral microscopy to diagnose asymptomatic and symptomatic non-chlamydial, non-gonococcal urethritis (NCNGU) in men is a cost-effective strategy to avert pelvic inflammatory disease (PID), ectopic pregnancy or infertility in female partners. Outputs from a transmission dynamic model of NCNGU in a population of 16-30 year olds in England simulating the number of consultations, PID cases and patients treated over time amongst others, were used along with secondary data to undertake a cost-effectiveness analysis carried out from a health care provider perspective. The main outcome measure was cost per case of PID averted. A secondary outcome measure was cost per major outcome averted, where a major outcome is a case of symptomatic PID, ectopic pregnancy, or infertility. Offering a limited number of asymptomatic men urethral microscopy was more effective than the current practice of no microscopy in terms of reducing the number of cases of PID with an incremental cost-effectiveness ratio of £15,700, meaning that an investment of £15,800 is required to avert one case of PID. For major outcomes averted, offering some asymptomatic men urethral microscopy was again found to be more effective than no microscopy, but here an investment of £49,900 is required to avert one major outcome. Testing asymptomatic men for NCNGU in a small number of genitourinary medicine settings in England is not cost-effective, and thus by maintaining the current practice of not offering this patient group microscopy, this continues to make savings for the health care provider.

The Ballseye programme: a mixed-methods programme of research in traditional sexual health and alternative community settings to improve the sexual health of men in the UK

Background

Sexually transmitted infection (STI) diagnoses are increasing and efforts to reduce transmission have failed. There are major uncertainties in the evidence base surrounding the delivery of STI care for men.

Aim

To improve the sexual health of young men in the UK by determining optimal strategies for STI testing and care

Objectives

To develop an evidence-based clinical algorithm for STI testing in asymptomatic men; model mathematically the epidemiological and economic impact of removing microscopy from routine STI testing in asymptomatic men; conduct a pilot randomised controlled trial (RCT) of accelerated partner therapy (APT; new models of partner notification to rapidly treat male sex partners of people with STIs) in primary care; explore the acceptability of diverse venues for STI screening in men; and determine optimal models for the delivery of screening.

Design

Systematic review of the clinical consequences of asymptomatic non-chlamydial, non-gonococcal urethritis (NCNGU); case–control study of factors associated with NCNGU; mathematical modelling of the epidemiological and economic impact of removing microscopy from asymptomatic screening and cost-effectiveness analysis; pilot RCT of APT for male sex partners of women diagnosed withChlamydia trachomatisinfection in primary care; stratified random probability sample survey of UK young men; qualitative study of men’s views on accessing STI testing; SPORTSMART pilot cluster RCT of two STI screening interventions in amateur football clubs; and anonymous questionnaire survey of STI risk and previous testing behaviour in men in football clubs.

Settings

General population, genitourinary medicine clinic attenders, general practice and community contraception and sexual health clinic attenders and amateur football clubs.

Participants

Men and women.

Interventions

Partner notification interventions: APTHotline [telephone assessment of partner(s)] and APTPharmacy [community pharmacist assessment of partner(s)]. SPORTSMART interventions: football captain-led and health adviser-led promotion of urine-based STI screening.

Main outcome measures

For the APT pilot RCT, the primary outcome, determined for each contactable partner, was whether or not they were considered to have been treated within 6 weeks of index diagnosis. For the SPORTSMART pilot RCT, the primary outcome was the proportion of eligible men accepting screening.

Results

Non-chlamydial, non-gonococcal urethritis is not associated with significant clinical consequences for men or their sexual partners but study quality is poor (systematic review). Men with symptomatic and asymptomatic NCNGU and healthy men share similar demographic, behavioural and clinical variables (case–control study). Removal of urethral microscopy from routine asymptomatic screening is likely to lead to a small rise in pelvic inflammatory disease (PID) but could save > £5M over 20 years (mathematical modelling and health economics analysis). In the APT pilot RCT the proportion of partners treated by the APTHotline [39/111 (35%)], APTPharmacy [46/100 (46%)] and standard patient referral [46/102 (45%)] did not meet national standards but exceeded previously reported outcomes in community settings. Men’s reported willingness to access self-sampling kits for STIs and human immunodeficiency virus infection was high. Traditional health-care settings were preferred but sports venues were acceptable to half of men who played sport (random probability sample survey). Men appear to prefer a ‘straightforward’ approach to STI screening, accessible as part of their daily activities (qualitative study). Uptake of STI screening in the SPORTSMART RCT was high, irrespective of arm [captain led 28/56 (50%); health-care professional led 31/46 (67%); poster only 31/51 (61%)], and costs were similar. Men were at risk of STIs but previous testing was common.

Conclusions

Men find traditional health-care settings the most acceptable places to access STI screening. Self-sampling kits in football clubs could widen access to screening and offer a public health impact for men with limited local sexual health services. Available evidence does not support an association between asymptomatic NCNGU and significant adverse clinical outcomes for men or their sexual partners but the literature is of poor quality. Similarities in characteristics of men with and without NCNGU precluded development of a meaningful clinical algorithm to guide STI testing in asymptomatic men. The mathematical modelling and cost-effectiveness analysis of removing all asymptomatic urethral microscopy screening suggests that this would result in a small rise in adverse outcomes such as PID but that it would be highly cost-effective. APT appears to improve outcomes of partner notification in community settings but outcomes still fail to meet national standards. Priorities for future work include improving understanding of men’s collective behaviours and how these can be harnessed to improve health outcomes; exploring barriers to and facilitators of opportunistic STI screening for men attending general practice, with development of evidence-based interventions to increase the offer and uptake of screening; further development of APT for community settings; and studies to improve knowledge of factors specific to screening men who have sex with men (MSM) and, in particular, how, with the different epidemiology of STIs in MSM and the current narrow focus on chlamydia, this could negatively impact MSM’s sexual health.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme.

Chlamydia screening and prophylactic treatment in termination of pregnancy clinics in the Netherlands and Great Britain: a qualitative study

BACKGROUND

Women having a termination of pregnancy (TOP) have higher rates of Chlamydia trachomatis (CT) than the general population. In this study, we explored CT treatment and prevention in Dutch TOP clinics in comparison to that provided in Great Britain (GB).

METHODS

A qualitative study including 14 semi-structured interviews with health care professionals (HCPs) in TOP clinics (the Netherlands: 9, GB: 5). Interviews were recorded, transcribed, and analysed by thematic content analysis.

RESULTS

Prophylactic treatment with azithromycin is routinely prescribed after surgical TOP, but not after medical TOP ('abortion pill'). Sexually transmitted infections (STI) tests are offered to clients who are considered at high risk of having STI. Uptake varies according to health insurance coverage of STI testing. Some Dutch clinics are able to provide free testing for women under 25 years of age. Sexual health counselling is often limited to discussing birth control. The major difference between the Netherlands and GB is that GB TOP clinics more often offer free STI testing and prophylaxis to their clients.

CONCLUSION

HCPs in Dutch TOP clinics consider STI testing an important part of their service, but financial barriers prevent testing on location. Dutch TOP clinics should offer STI tests to all women, and collaboration with public health services could improve STI testing and counselling for young people. Furthermore, clinics should treat all TOP clients with prophylactic azithromycin. This could prevent CT and other upper genital tract post-abortion infections.

Sexual health promotion for young people delivered via digital media: a scoping review

Background

Young people are at risk of poor sexual health and are, therefore, in need of comprehensive, effective sexual health education. Young people are confident and constant users of digital technology, such as the internet and mobile phones, and there are many innovative possibilities for sexual health education involving these technologies.

Objectives

To summarise evidence on effectiveness, cost-effectiveness and mechanism of action of interactive digital interventions (IDIs) for sexual health; optimal practice for intervention development; contexts for successful implementation; research methods for digital intervention evaluation; and the future potential of sexual health promotion via digital media.

Design

Literature review of evidence on digital interventions for sexual health for young people, integrating the findings with the views of young people, parents and experts in digital media/sexual health. IDIs are defined as digital media programmes that provide health information and tailored decision support, behaviour-change support and/or emotional support. We focus on sexual well-being for young people aged 13–24 years in the UK.

Results

There are many imaginative IDIs for sexual health promotion, but few interventions address issues that are important to young people, such as sexual pleasure and relationships. It is vital to collaborate with young people and to use Behaviour-Change Theory in designing interventions. We located 19 randomised controlled trials of IDIs for sexual health promotion for young people, finding a moderate effect on sexual health knowledge [standardised mean difference (SMD) 0.54, 95% confidence interval (CI) 0.17 to 0.92], a small effect on confidence (self-efficacy) (SMD 0.11, 95% CI 0.02 to 0.20) and a positive effect on sexual behaviour (odds ratio 1.28, 95% CI 1.01 to 1.61), but no significant effects on safer sex intention or biological outcomes. One study suggests that IDIs may be as good as face-to-face interventions for sexual health knowledge and safer sex intention. There are no existing data on the cost-effectiveness of IDIs for sexual health promotion. The impact of an IDI will be determined by the proportion of the target population reached, intervention efficacy, adoption in a setting, how well it is delivered and maintenance/sustainability. All of these elements must be addressed for IDIs to be successful. More collaboration is needed to capitalise on the knowledge of users and stakeholders, the design and software skills of the commercial sector and the theoretical expertise and evaluation skills of academia.

Conclusions

IDIs are effective for knowledge acquisition and sexual behaviour, and could usefully contribute to sexual health education in schools, in clinic settings and online; however, there are obstacles to overcome, such as access to information technology and ensuring the quality and safety of interventions.

Future work

More evidence is needed on the best designs for interventions (e.g. choice of behaviour-change mechanisms and interactive features) and the best models of delivery (e.g. setting, modes of delivery, methods of facilitation and support for engagement) to improve sexual behaviour, biological outcomes and sexual well-being in a cost-effective way.

Funding

The National Institute for Health Research Public Health Research programme.

Chlamydia screening for pregnant women aged 16-25 years attending an antenatal service: a cost-effectiveness study

OBJECTIVE

Determine the cost-effectiveness of screening all pregnant women aged 16-25 years for chlamydia compared with selective screening or no screening.

DESIGN

Cost effectiveness based on a decision model.

SETTING

Antenatal clinics in Australia.

SAMPLE

Pregnant women, aged 16-25 years.

METHODS

Using clinical data from a previous study, and outcomes data from the literature, we modelled the short-term perinatal (12-month time horizon) incremental direct costs and outcomes from a government (as the primary third-party funder) perspective for chlamydia screening. Costs were derived from the Medicare Benefits Schedule, Pharmaceutical Benefits Scheme, and average cost-weights reported for hospitalisations classified according to the Australian refined diagnosis-related groups.

MAIN OUTCOME MEASURES

Direct costs of screening and managing chlamydia complications, number of chlamydia cases detected and treated, and the incremental cost-effectiveness ratios were estimated and subjected to sensitivity analyses.

RESULTS

Assuming a chlamydia prevalence rate of 3%, screening all antenatal women aged 16-25 years at their first antenatal visit compared with no screening was $34,931 per quality-adjusted life-years gained. Screening all women could result in cost savings when chlamydia prevalence was higher than 11%. The incremental cost-effectiveness ratios were most sensitive to the assumed prevalence of chlamydia, the probability of pelvic inflammatory disease, the utility weight of a positive chlamydia test and the cost of the chlamydia test and doctor's appointment.

CONCLUSION

From an Australian government perspective, chlamydia screening of all women aged 16-25 years old during one antenatal visit was likely to be cost-effective compared with no screening or selective screening, especially with increasing chlamydia prevalence.

TWEETABLE ABSTRACT

Chlamydia screening for all pregnant women aged 16-25 years during an antenatal visit is cost effective.

Optimizing strategies for population-based chlamydia infection screening among young women: an age-structured system dynamics approach

Background

Chlamydia infection (CT) is one of the most commonly reported sexually transmitted diseases. It is often referred to as a “silent” disease with the majority of infected people having no symptoms. Without early detection, it can progress to serious reproductive and other health problems. Economical identification of asymptomatically infected is a key public health challenge. Increasing evidence suggests that CT infection risk varies over the range of adolescence. Hence, age-dependent screening strategies with more frequent testing for certain age groups of higher risk may be cost-saving in controlling the disease.

Methods

We study the optimization of age-dependent screening strategies for population-based chlamydia infection screening among young women. We develop an age-structured compartment model for CT natural progress, screening, and treatment. We apply parameter optimization on the resultant PDE-based system dynamical models with the objective of minimizing the total care spending, including screening and treatment costs during the program period and anticipated costs of treating the sequelae afterwards). For ease of practical implementation, we also search for the best screening initiation age for strategies with a constant screening frequency.

Results

The optimal age-dependent strategies identified outperform the current CDC recommendations both in terms of total care spending and disease prevalence at the termination of the program. For example, the age-dependent strategy that allows monthly screening rate changes can save about 5 % of the total spending. Our results suggest early initiation of CT screening is likely beneficial to the cost saving and prevalence reduction. Finally, our results imply that the strategy design may not be sensitive to accurate quantification of the age-specific CT infection risk if screening initiation age and screening rate are the only decisions to make.

Conclusions

Our research demonstrates the potential economic benefit of age-dependent screening strategy design for population-based screening programs. It also showcases the applicability of age-structured system dynamical modeling to infectious disease control with increasing evidence on the age differences in infection risk. The research can be further improved with consideration of the difference between first-time infection and reinfection, as well as population heterogeneity in sexual partnership.

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

OBJECTIVE

In three pilot regions of The Netherlands, all 16-29 year olds were invited to participate in three annual rounds of Chlamydia screening. The aim of the present study is to evaluate the cost-effectiveness of repeated Chlamydia screening, based on empirical data.

METHODS

A mathematical model was employed to estimate the influence of repeated screening on prevalence and incidence of Chlamydial infection. A model simulating the natural history of Chlamydia was combined with cost and utility data to estimate the number of major outcomes and quality-adjusted life-years (QALYs) associated with Chlamydia. Six screening scenarios (16-29 years annually; 16-24 years annually; women only; biennial screening; biennial screening women only; screening every five years) were compared with no screening in two sexual networks, representing both lower ('national network') and higher ('urban network') baseline prevalence. Incremental cost-effectiveness ratios (ICERs) for the different screening scenarios were estimated. Uncertainty and sensitivity analyses were performed.

RESULTS

In all scenarios and networks, cost per major outcome averted are above €5000. Cost per QALY are at least €50,000. The default scenario as piloted in the Netherlands was least cost-effective, with ICERs of €232,000 in the national and €145,000 in the urban sexual network. Results were robust in sensitivity analyses.

CONCLUSIONS

It is unlikely that repeated rounds of Chlamydia screening will be cost-effective. Only at high levels of willingness to pay for a QALY (>€50,000) screening may be more cost-effective than no screening.

Cost-effectiveness of routine varicella vaccination using the measles, mumps, rubella and varicella vaccine in France: an economic analysis based on a dynamic transmission model for varicella and herpes zoster

PURPOSE

Each year in France, varicella and zoster affect large numbers of children and adults, resulting in medical visits, hospitalizations for varicella- and zoster-related complications, and societal costs. Disease prevention by varicella vaccination is feasible, wherein a plausible option involves replacing the combined measles, mumps, and rubella (MMR) vaccine with the combined MMR and varicella (MMRV) vaccine. This study aimed to: (1) assess the cost-effectiveness of adding routine varicella vaccination through MMRV, using different vaccination strategies in France; and (2) address key uncertainties, such as the economic consequences of breakthrough varicella cases, the waning of vaccine-conferred protection, vaccination coverage, and indirect costs.

METHODS

Based on the outputs of a dynamic transmission model that used data on epidemiology and costs from France, a cost-effectiveness model was built. A conservative approach was taken regarding the impact of varicella vaccination on zoster incidence by assuming the validity of the hypothesis of an age-specific boosting of immunity against varicella.

FINDINGS

The model determined that routine MMRV vaccination is expected to be a cost-effective option, considering a cost-effectiveness threshold of €20,000 per quality-adjusted life-year saved; routine vaccination was cost-saving from the societal perspective. Results were driven by a large decrease in varicella incidence despite a temporary initial increase in the number of zoster cases due to the assumption of exogenous boosting. In the scenario analyses, despite moderate changes in assumptions about incidence and costs, varicella vaccination remained a cost-effective option for France.

IMPLICATIONS

Routine vaccination with MMRV was associated with high gains in quality-adjusted life-years, substantial reduction in the occurrences of varicella- and zoster-related complications, and few deaths due to varicella. Routine MMRV vaccination is also expected to provide reductions in costs related to hospitalizations, medication use, and general-practitioner visits, as well as indirect costs, and it is expected to be a cost-effective intervention in France (GSK study identifier: HO-12-6924).

Cost-effectiveness of screening men in Maricopa County jails for chlamydia and gonorrhea to avert infections in women

BACKGROUND

Chlamydia and gonorrhea infections can lead to serious and costly sequelae in women, but sequelae in men are rare. In accordance with the Centers for Disease Control and Prevention guidelines, female jail inmates in Maricopa County (Phoenix area), Arizona, are screened for these infections. Owing to lack of evidence of screening benefits in men, male inmates are tested and treated based on symptoms only.

METHODS

We developed a probabilistic simulation model to simulate chlamydia and gonorrhea infections in Maricopa County jail male inmates and transmissions to female partners per year. We estimated the cost-effectiveness of screening as the cost per infection averted. Costs were estimated from the perspective of the Maricopa County Department of Public Health and the Correctional Health Services.

RESULTS

Compared with symptom-based testing and treating strategy, screening male arrestees of all ages and only those 35 years or younger yielded the following results: averted approximately 556 and 491 cases of infection in women at a cost of approximately US $1240 and $860 per case averted, respectively, if screened during physical examination (between days 8 and 14 from entry to jail), and averted approximately 1100 and 995 cases of infections averted at a cost of US $1030 and $710 per infection averted, respectively, if screened early, within 2 to 3 days from entry to jail.

CONCLUSIONS

Screening of male inmates incurs a modest cost per infection averted in women compared with symptom-based testing. Screening in correctional settings can be used by public health programs to reduce disease burden, sequelae, and associated costs.

How robust are the natural history parameters used in chlamydia transmission dynamic models? A systematic review

Transmission dynamic models linked to economic analyses often form part of the decision making process when introducing new chlamydia screening interventions. Outputs from these transmission dynamic models can vary depending on the values of the parameters used to describe the infection. Therefore these values can have an important influence on policy and resource allocation. The risk of progression from infection to pelvic inflammatory disease has been extensively studied but the parameters which govern the transmission dynamics are frequently neglected. We conducted a systematic review of transmission dynamic models linked to economic analyses of chlamydia screening interventions to critically assess the source and variability of the proportion of infections that are asymptomatic, the duration of infection and the transmission probability. We identified nine relevant studies in Pubmed, Embase and the Cochrane database. We found that there is a wide variation in their natural history parameters, including an absolute difference in the proportion of asymptomatic infections of 25% in women and 75% in men, a six-fold difference in the duration of asymptomatic infection and a four-fold difference in the per act transmission probability. We consider that much of this variation can be explained by a lack of consensus in the literature. We found that a significant proportion of parameter values were referenced back to the early chlamydia literature, before the introduction of nucleic acid modes of diagnosis and the widespread testing of asymptomatic individuals. In conclusion, authors should use high quality contemporary evidence to inform their parameter values, clearly document their assumptions and make appropriate use of sensitivity analysis. This will help to make models more transparent and increase their utility to policy makers.

Valuing the health states associated with Chlamydia trachomatis infections and their sequelae: a systematic review of economic evaluations and primary studies

OBJECTIVES

Economic evaluations of interventions to prevent and control sexually transmitted infections such as Chlamydia trachomatis are increasingly required to present their outcomes in terms of quality-adjusted life-years using preference-based measurements of relevant health states. The objectives of this study were to critically evaluate how published cost-effectiveness studies have conceptualized and valued health states associated with chlamydia and to examine the primary evidence available to inform health state utility values (HSUVs).

METHODS

A systematic review was conducted, with searches of six electronic databases up to December 2012. Data on study characteristics, methods, and main results were extracted by using a standard template.

RESULTS

Nineteen economic evaluations of relevant interventions were included. Individual studies considered different health states and assigned different values and durations. Eleven studies cited the same source for HSUVs. Only five primary studies valued relevant health states. The methods and viewpoints adopted varied, and different values for health states were generated.

CONCLUSIONS

Limitations in the information available about HSUVs associated with chlamydia and its complications have implications for the robustness of economic evaluations in this area. None of the primary studies could be used without reservation to inform cost-effectiveness analyses in the United Kingdom. Future debate should consider appropriate methods for valuing health states for infectious diseases, because recommended approaches may not be suitable. Unless we adequately tackle the challenges associated with measuring and valuing health-related quality of life for patients with chlamydia and other infectious diseases, evaluating the cost-effectiveness of interventions in this area will remain problematic.

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.

Development status and future prospects for a vaccine against Chlamydia trachomatis infection

Chlamydia trachomatis continues to be the most commonly reported sexually transmitted bacterial infection in many countries with more than 100 million new cases estimated annually. These acute infections translate into significant downstream health care costs, particularly for women, where complications can include pelvic inflammatory disease and other disease sequelae such as tubal factor infertility. Despite years of research, the immunological mechanisms responsible for protective immunity versus immunopathology are still not well understood, although it is widely accepted that T cell driven IFN-g and Th17 responses are critical for clearing infection. While antibodies are able to neutralize infections in vitro, alone they are not protective, indicating that any successful vaccine will need to elicit both arms of the immune response. In recent years, there has been an expansion in the number and types of antigens that have been evaluated as vaccines, and combined with the new array of mucosal adjuvants, this aspect of chlamydial vaccinology is showing promise. Most recently, the opportunities to develop successful vaccines have been given a significant boost with the development of a genetic transformation system for Chlamydia, as well as the identification of the key role of the chlamydial plasmid in virulence. While still remaining a major challenge, the development of a successful C. trachomatis vaccine is starting to look more likely.

Chlamydia trachomatis infection among women 26 to 39 years of age in the United States, 1999 to 2010

Using data from a nationally representative survey, we identified predictors of chlamydial infection in women aged 26 to 39 years. Chlamydia prevalence was low overall but varied by sociodemographics and sexual behaviors. Findings support current recommendations that women older than 25 years should not be routinely screened for chlamydial infection.

Dynamic transmission modeling: a report of the ISPOR-SMDM Modeling Good Research Practices Task Force Working Group-5

The transmissible nature of communicable diseases is what sets them apart from other diseases modeled by health economists. The probability of a susceptible individual becoming infected at any one point in time (the force of infection) is related to the number of infectious individuals in the population, will change over time, and will feed back into the future force of infection. These nonlinear interactions produce transmission dynamics that require specific consideration when modeling an intervention that has an impact on the transmission of a pathogen. Best practices for designing and building these models are set out in this paper.

Dynamic transmission modeling: a report of the ISPOR-SMDM Modeling Good Research Practices Task Force--5

The transmissible nature of communicable diseases is what sets them apart from other diseases modeled by health economists. The probability of a susceptible individual becoming infected at any one point in time (the force of infection) is related to the number of infectious individuals in the population, will change over time, and will feed back into the future force of infection. These nonlinear interactions produce transmission dynamics that require specific consideration when modeling an intervention that has an impact on the transmission of a pathogen. Best practices for designing and building these models are set out in this article.

Knowledge of sexually transmissible infections: a comparison of prisoners and the general population

The World Health Organization (WHO) has identified a failure to provide education for vulnerable populations such as prisoners as a contributing factor to the epidemic of sexually transmissible infections (STIs). Despite this recognition, little is known about prisoners' level of knowledge of STIs compared with the general population. Using computer-assisted telephone interviews, we compared a representative sample of 2289 Australian prisoners, aged 18–59 years from New South Wales and Queensland prisons with a representative community sample of 3536 participants from these two states. Prisoners had significantly better knowledge than the general community of chlamydia-related questions, while knowledge of herpes (genital and oral) was slightly better in the community sample. Prisoners who were aged over 25 years, not married, female, self-identified as either homosexual or bisexual and reported a history of STIs tended to have better STI knowledge levels. Despite their more disadvantaged backgrounds, prisoners demonstrated relatively good health literacy in relation to STIs. Ongoing education about the transmission risks of STIs for prisoners and the general community is needed.

Modelling the epidemiology of infectious diseases for decision analysis: a primer

The number of economic evaluations related to infectious disease topics has increased over the last 2 decades. However, many such evaluations rely on models that do not take into account unique features of infectious diseases that can affect the estimated value of interventions against them. These include their transmissibility from infected to susceptible individuals, the possibility of acquiring natural immunity following recovery from infection and the uncertainties that arise as a result of their complex natural history and epidemiology. Modellers conducting economic evaluations of infectious disease interventions need to know the main features of different types of infectious disease models, the situations in which they should be applied and the effects of model choices on the cost effectiveness of interventions.

Epidemiological features and determinants for Chlamydia trachomatis infection among women in Catalonia, Spain

We determined the prevalence of Chlamydia trachomatis (CT) infection and risk factors for its acquisition by women aged less than 35 years who were attending sexual health centres in the province of Barcelona in 2007. A convenience sample of 397 adolescents and young adult women aged between 16 and 35 years, stratified by age and recruitment site, were tested using realtime polymerase chain reaction by CT DNA. A standardized questionnaire was used to collect epidemiological and behavioural data on the participants, which were analysed in a multivariate logistic regression model. The overall prevalence of CT was 4%, significantly higher in those under 25 years of age (5.8% versus 1.6% over 25). The independent risk factors for CT infection were: foreign origin (odds ratio [OR] 4.7; confidence interval [CI] 1.02-21.8), having had a sexual partner in the last three months (OR 4.59; CI 1.16-18.08) and tobacco use the last 12 months (OR 6.38; CI 1.16-34.93). In conclusion, this is the first study performed in Catalonia showing a high prevalence of CT in young women, consistent with trends in the rest of Europe. Systematic monitoring of CT infection in sentinel populations such as this will inform future targeted screening programmes in our setting.

Economic evaluation, human immunodeficiency virus infection and screening: a review and critical appraisal of economic studies

OBJECTIVES

The aim of this study was to review, systematically and critically, evidence used to derive estimates of cost-effectiveness of human immunodeficiency virus (HIV) screening.

METHODS

A systematic review was conducted. Searched were three main electronic bibliographic databases from 1993 to 2008 using key words including HIV, mass screening, HAART, economic evaluation, cost-effectiveness analysis, modeling. We included studies of sexually transmitted HIV infection in both sexes, including studies comparing diagnostic testing protocols and partner notification. Outcomes included were cases of HIV infection detected, deterioration to the AIDS state, secondary transmission of HIV, the quality-adjusted life-years/survival, costs, and cost-effectiveness of HIV screening.

RESULTS

Eighty-four papers were identified; ten of which were formal economic evaluations, one cost study, three effectiveness studies, and three systematic reviews of HIV prevention programs. The predominant assertion was that HIV screening is cost-effective; methodological problems, such as the preponderance of static models which are inappropriate for infectious diseases, varying perspectives from which the studies were analyzed, and arbitrary threshold incremental cost-effectiveness ratio levels, limited the validity of these findings, and their usefulness in informing health policy decisions.

CONCLUSIONS

The majority of published economic evaluations are based on inappropriate static models. This flaw renders the results of these studies as inconclusive and the purported cost-effectiveness of HIV screening debatable. The results of this review could form a basis for consideration of further research and analysis by health economists into the cost-effectiveness of HIV screening.

Relative efficiency of chlamydia screening in non-clinical settings in two California counties

We examined the relative efficiency of non-clinical sites to screen for chlamydia in youth and young adults. Chlamydia screening targeting youth (under 30 years of age) was performed at non-clinical sites in high-morbidity neighbourhoods of two California counties. Venues were subdivided into community outreach, schools, parenting centres and drug treatment/correctional facilities. Relative efficiency was estimated with multivariate Poisson regression using incidence of chlamydia per person-hours labour adjusting for strategy and county. Among the 1514 youths screened, the overall prevalence of chlamydia was 5.5%. By venue, the highest prevalence was in drug treatment/correction facilities at 11.1% followed by parenting centres at 6.3%, community outreach at 4.9% and schools at 4.6%. Drug treatment/correctional facilities were the most labour time efficient at 9.9 person-hours per chlamydia case. Schools and parenting centres had the lowest cost per screen at 0.9 person-hours per screen. Adjusted relative labour time efficiency (chlamydia cases per paid person-hour) was significantly higher in schools, 2.0 (95% confidence interval [CI] 1.0-4.2), parenting centres, 3.2 (95% CI 1.6-6.6) and drug treatment/correctional facilities, 2.9 (95% CI 1.0-7.8), compared with community outreach. In conclusion, parenting centres and drug treatment centres and correctional facilities are the most efficient venues for chlamydia screening.

A cost-effectiveness analysis of the Chlamydia Monday - A community-based intervention to decrease the prevalence of chlamydia in Sweden

Aims: The study was undertaken to assess the cost-effectiveness of the Chlamydia Monday, 2007. This is a community-based intervention aimed at reducing the prevalence of chlamydia by information and increased availability of testing, treatment and contact tracing in Stockholm. The aim was to analyze the cost-effectiveness by estimating costs, savings and effects on health associated with the intervention, and to determine if cost-effectiveness varies between men and women. Methods: A societal perspective was adopted, meaning all significant costs and consequences were taken into consideration, regardless of who experienced them. A cost-effectiveness model was constructed including costs of the intervention, savings due to avoiding potential costs associated with medical sequels of chlamydia infection, and health gains measured as quality adjusted life years (QALY). Sensitivity analyses were done to explore model and result uncertainty. Results: Total costs were calculated to be 66,787.21; total savings to 30,370.14; and total health gains to 9.852324 QALYs (undiscounted figures). The discounted cost per QALY was 8,346.05 (10,810.77/QALY for women and 6,085.35/QALY for men). Sensitivity analyses included changes in effectiveness, variation of prevalence, reduced risk of sequel progression, inclusion of prevented future production loss and shortened duration for chronic conditions. The cost per QALY was consistently less than 50,000, which is often regarded as cost-effective in a Swedish context. Conclusions: The Chlamydia Monday has been demonstrated by this study to be a cost-effective intervention and should be considered a wise use of society’s resources.

The cost-effectiveness of screening men for Chlamydia trachomatis: a review of the literature

BACKGROUND

An important consideration in determining whether to implement or continue a program to screen men for chlamydia is its cost-effectiveness. A review of the literature on the cost-effectiveness of screening men for chlamydia could potentially provide guidance.

METHODS

An Ovid Medline search was conducted for articles published between 1990 and July 2007 using terms for cost, chlamydia, and male. This search returned 175 articles; 25 were retained after eliminating those not relevant to cost-effectiveness studies of male chlamydia screening. We added 4 articles that were in-press or are published in this issue, for a total of 29. These articles were examined for common themes and their results summarized.

RESULTS

The reviewed studies examined both proactive and opportunistic screening and included screening of risk groups and of the general population. Some older studies included enzyme immunoassays; more recent studies featured nucleic acid amplification assays. Six studies used dynamic transmission models. Fourteen studies analyzed male and female chlamydia screening interventions. Several contained sufficient data to examine the cost-effectiveness of male screening compared with female screening. Male screening was preferred to expanded female screening in 1 study. In other studies, combined male and female screening programs were cost-saving.

CONCLUSIONS

Studies comparing chlamydia screening in men with chlamydia screening in women may be the most useful for guidance to programs. The studies which compare the 2 generally have found that screening men from the general population is not preferred to screening women from the general population, although 1 study found that screening of men from risk groups can be cost-effective compared with screening women from the general population.

The Philadelphia High-School STD Screening Program: key insights from dynamic transmission modeling

BACKGROUND

The Philadelphia high-school STD Screening Program (PHSSP) represents an innovative approach to screening-based control of Chlamydia trachomatis infection. The program has been associated with significant reductions in Chlamydia trachomatis prevalence in young females in Philadelphia. We sought to assess program cost-effectiveness in a manner that allowed us to quantify the impact of including males students in the screened population.

METHODS

We created a dynamic transmission model using a susceptible-infectious-resistant-susceptible framework. The model was parameterized using PHSSP program data, supplemented by available data from the medical and public health literature, and was used to project the impact of screening on disease burden, quality adjusted survival, and costs.

RESULTS

A well-calibrated model suggests that high-school based screening is highly cost-effective in the Philadelphia context. Five important insights are gained through dynamic transmission modeling of the PHSSP: (i) the importance of screening males can be appreciated using a dynamic transmission model; (ii) the attractiveness of screening males is inversely related to equilibrium prevalence in males; (iii) including males enhances both effectiveness and economic attractiveness of screening; (iv) rebound in prevalence does not greatly diminish the cost-effectiveness of screening; and (v) increasing program expenditures via increased screening coverage decreases net societal costs, due to diminished disease transmission.

CONCLUSIONS

The current PHSSP is highly cost-effective relative to other commonly accepted interventions. Effectiveness and cost-effectiveness of this program are enhanced by including males. This, and other important attributes of the program, is best appreciated when a dynamic transmission model is used for program evaluation.

Screening young adults for prevalent chlamydial infection in community settings

PURPOSE

Community-based testing may identify young adults in the general population with sexually transmitted chlamydial infection. To develop selective screening guidelines appropriate for community settings, the authors conducted a cross-sectional analysis of the National Longitudinal Study of Adolescent Health Wave III (April 2, 2001, to May 9, 2002).

METHODS

Separately for women and men, we developed three predictive models by using unconditional multiple logistic regression for survey data. To account for racial/ethnic disparity in prevalence, initial models included identical predictor characteristics plus information on 1) respondent's race/ethnicity; or 2) respondent's most recent partner's race/ethnicity; or 3) no information on race/ethnicity.

RESULTS

Chlamydia trachomatis diagnosis was available for 10,928 (88.6%) of the sexually experienced respondents. A combination of five characteristics for women and six characteristics for men identified approximately 80% of infections when testing

CONCLUSION

The use of race/ethnicity in any screening algorithm is problematic and controversial, but the model without race information missed many diagnoses in the minority groups. Universal screening in high-prevalence regions and selective screening in low-prevalence regions may be one method of reaching the affected populations while avoiding the stigma of guidelines incorporating race/ethnicity.

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Key Words Collapse

MESH Headings

• Adolescent
• Adult
• Chlamydia Infections/diagnosis
• Chlamydia Infections/epidemiology
• Chlamydia Infections/ethnology
• Chlamydia trachomatis/isolation & purification
• Community Health Services
• Cross-Sectional Studies
• Female
• Health Status Disparities
• Healthcare Disparities
• Humans
• Male
• Mass Screening/methods
• Prevalence
• Risk Assessment
• Sexual Behavior
• Socioeconomic Factors
• United States/epidemiology

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Grants

• R21 HD050739 NICHD NIH HHS
• R21 HD050739-01 NICHD NIH HHS

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Affiliation(s)

Cheryl R Stein Department of Epidemiology, School of Public Health, University of North Carolina at Chapel Hill, USA.
Jay S Kaufman
Carol A Ford
Peter A Leone
Paul J Feldblum
William C Miller

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Costs and health consequences of chlamydia management strategies among pregnant women in sub-Saharan Africa

OBJECTIVES

Chlamydia is the most common bacterial sexually transmitted infection worldwide and a major cause of morbidity-particularly among women and neonates. We compared costs and health consequences of using point-of-care (POC) tests with current syndromic management among antenatal care attendees in sub-Saharan Africa. We also compared erythromycin with azithromycin treatment and universal with age-based chlamydia management.

METHODS

A decision analytical model was developed to compare diagnostic and treatment strategies, using Botswana as a case. Model input was based upon (1) a study of pregnant women in Botswana, (2) literature reviews and (3) expert opinion. We expressed the study outcome in terms of costs (US$), cases cured, magnitude of overtreatment and successful partner treatment.

RESULTS

Azithromycin was less costly and more effective than erythromycin. Compared with syndromic management, testing all attendees on their first visit with a 75% sensitive POC test increased the number of cases cured from 1500 to 3500 in a population of 100,000 women, at a cost of US$38 per additional case cured. This cost was lower in high-prevalence populations or if testing was restricted to teenagers. The specific POC tests provided the advantage of substantial reductions in overtreatment with antibiotics and improved partner management.

CONCLUSIONS

Using POC tests to diagnose chlamydia during antenatal care in sub-Saharan Africa entails greater health benefits than syndromic management does-and at acceptable costs-especially when restricted to younger women. Changes in diagnostic strategy and treatment regimens may improve people's health and even reduce healthcare budgets.

The cost effectiveness of opportunistic chlamydia screening in England

BACKGROUND/AIM

The National Chlamydia Screening Programme (NCSP) is being implemented in England. This study aims to estimate the cost effectiveness of (a) the NCSP strategy (annual screening offer to men and women aged under 25 years) and (b) alternative screening strategies.

METHODS

A stochastic, individual based, dynamic sexual network model was combined with a cost effectiveness model to estimate the complications and associated costs of chlamydial infection. The model was constructed and parameterised from the perspective of the National Health Service (NHS) (England), including the direct costs of infection, complications and screening. Unit costs were derived from standard data sources and published studies. The average and incremental cost effectiveness ratio (cost per major outcome averted or quality adjusted life year (QALY) gained) of chlamydia screening strategies targeting women and/or men of different age groups was estimated. Sensitivity analyses were done to explore model uncertainty.

RESULTS

All screening strategies modelled are likely to cost the NHS money and improve health. If pelvic inflammatory disease (PID) progression is less than 10% then screening at any level is unlikely to be cost effective. However, if PID progression is 10% or higher the NCSP strategy compared to no screening appears to be cost effective. The incremental cost effectiveness analysis suggests that screening men and women aged under 20 years is the most beneficial strategy that falls below accepted thresholds. There is a high degree of uncertainty in the findings.

CONCLUSIONS

Offering an annual screening test to men and women aged under 20 years may be the most cost effective strategy (that is, under accepted thresholds) if PID progression is 10% or higher.

Cost effectiveness of home based population screening for Chlamydia trachomatis in the UK: economic evaluation of chlamydia screening studies (ClaSS) project

OBJECTIVE

To investigate the cost effectiveness of screening for Chlamydia trachomatis compared with a policy of no organised screening in the United Kingdom.

DESIGN

Economic evaluation using a transmission dynamic mathematical model.

SETTING

Central and southwest England.

PARTICIPANTS

Hypothetical population of 50,000 men and women, in which all those aged 16-24 years were invited to be screened each year.

MAIN OUTCOME MEASURES

Cost effectiveness based on major outcomes averted, defined as pelvic inflammatory disease, ectopic pregnancy, infertility, or neonatal complications.

RESULTS

The incremental cost per major outcome averted for a programme of screening women only (assuming eight years of screening) was 22,300 pounds (33,000 euros; $45,000) compared with no organised screening. For a programme screening both men and women, the incremental cost effectiveness ratio was approximately 28,900 pounds. Pelvic inflammatory disease leading to hospital admission was the most frequently averted major outcome. The model was highly sensitive to the incidence of major outcomes and to uptake of screening. When both were increased the cost effectiveness ratio fell to 6200 pound per major outcome averted for screening women only.

CONCLUSIONS

Proactive register based screening for chlamydia is not cost effective if the uptake of screening and incidence of complications are based on contemporary empirical studies, which show lower rates than commonly assumed. These data are relevant to discussions about the cost effectiveness of the opportunistic model of chlamydia screening being introduced in England.

One to one interventions to reduce sexually transmitted infections and under the age of 18 conceptions: a systematic review of the economic evaluations

OBJECTIVE

To systematically review and critically appraise the economic evaluations of one to one interventions to reduce sexually transmitted infections (STIs) and teenage conceptions.

DESIGN

Systematic review.

DATA SOURCES

Search of four electronic bibliographic databases from 1990 to January 2006. Search keywords included teenage, pregnancy, adolescent, unplanned, unwanted, cost benefit, cost utility, economic evaluation, cost effectiveness and all terms for STIs, including specific diseases.

REVIEW METHODS

We included studies that evaluated a broad range of one to one interventions to reduce STIs. Outcomes included major outcomes averted, life years and quality adjusted life years (QALY). All studies were assessed against quality criteria.

RESULTS

Of 3,190 identified papers, 55 were included. The majority of studies found one to one interventions to be either cost saving or cost effective, although one highlighted the need to target the population to receive post-exposure prophylaxis to reduce transmission of HIV. Most studies used a static approach that ignores the potential re-infection of treated patients.

CONCLUSION

One to one interventions have been shown to be cost saving or cost effective but there are some limitations in applying this evidence to the UK policy context. More UK research using dynamic modelling approaches and QALYs would provide improved evidence, enabling more robust policy recommendations to be made about which one to one interventions are cost effective in reducing STIs in the UK setting. The results of this review can be used by policy makers, health economists and researchers considering further research in this area.

Risk selection and targeted interventions in community-based control of chlamydia

PURPOSE OF REVIEW

To describe recent developments in the community-based approach of high-risk groups for Chlamydia trachomatis infection, and to discuss the assessment of impact of selective systematic screening on the transmission of C. trachomatis in the community.

RECENT FINDINGS

Two large home-based screening programs in Europe have recently shown that systematic postal screening for C. trachomatis infection is feasible, but certain high-risk groups are poor participators. This underscores the need for risk selection and targeted approaches. A prediction rule has been developed which can assist in identifying high-risk groups and can be used as a tool for (self) selection for screening. The Internet has been shown to be a promising medium to promote chlamydia testing. School-based programs also succeed in including high-risk groups in screening programs. Recently developed dynamic simulation models, which take into account transmission of C. trachomatis, can assist in the development and evaluation of targeted screening strategies.

SUMMARY

Chlamydia will not likely be controlled by one standard approach. Risk selection strategies need further development and different systematic approaches at the community level, including postal screening, school-based screening, and the Internet may produce the desired public health effect of decreasing morbidity and reducing the transmission of C. trachomatis in the community.