How do changes in the population tested for chlamydia over time affect observed trends in chlamydia positivity? Analysis of routinely collected data from young women tested for chlamydia in family planning clinics in the Pacific Northwest (USA), between 2003 and 2010
Sarah C. Woodhall A D , Lizzi Torrone B , David Fine C , Sarah G. Salomon C , Wendy Nakatsukasa-Ono C , Kate Soldan A and Hillard Weinstock BA HIV & STI Department, Centre for Infectious Disease Surveillance and Control, Public Health England, London, UK.
B Division of STD Prevention, Centers for Disease Control and Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Atlanta, GA, USA.
C Cardea Services, Seattle, WA, USA.
D Corresponding author. Email: sarah.woodhall@phe.gov.uk
Sexual Health 12(6) 512-519 https://doi.org/10.1071/SH15044
Submitted: 13 March 2015 Accepted: 7 July 2015 Published: 14 September 2015
Abstract
Background: The proportion of chlamydia tests that are positive (positivity) is dependent on the population tested and the test technology used. The way in which changes in these variables might affect trends in positivity over time is investigated. Methods: Data from 15- to 24-year-old women tested for chlamydia in family planning clinics participating in the Infertility Prevention Project in the Pacific Northwest, United States (USA Public Health Service Region X) during 2003–2010 (n = 590 557) were analysed. Trends in positivity and in test, demographic and sexual behaviour variables were identified. Unadjusted and adjusted trends in chlamydia positivity were calculated using logistic regression. Results: The proportion of tests carried out using nucleic acid amplification tests (NAATs) increased dramatically during the analysis period in two states. Smaller changes in demographic and behavioural characteristics were seen. Controlling for test technology used had the largest effect on the trend in testing positive per year, leading to a fall in the calculated odds ratio of testing positive from 1.06 to 1.02 in Oregon, and from 1.07 to 1.02 in Idaho. Controlling for other variables had minimal effect on chlamydia positivity trends. Conclusions: Changes in NAAT use had a large effect on observed trends in chlamydia positivity over time in the two states where NAATs were introduced during the analysis period. While trends in chlamydia positivity may be a useful metric for monitoring chlamydia burden, it is important to consider changes in test type when interpreting these data.
References
[1] Centers for Disease Control and Prevention. Sexually transmitted disease surveillance, 2011. Atlanta: US Department of Health and Human Services, Centers for Disease Control and Prevention; 2012.[2] Burckhardt F, Warner P, Young H. What is the impact of change in diagnostic test method on surveillance data trends in Chlamydia trachomatis infection? Sex Transm Infect 2006; 82 24–30.
| What is the impact of change in diagnostic test method on surveillance data trends in Chlamydia trachomatis infection?Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD28%2FnslaktQ%3D%3D&md5=534d1ec01f2b8ad4208e7f5a5a6341ebCAS | 16461597PubMed |
[3] Miller WC. Epidemiology of chlamydial infection: are we losing ground? Sex Transm Infect 2008; 84 82–6.
| Epidemiology of chlamydial infection: are we losing ground?Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD1c3htlChtA%3D%3D&md5=60be9cecdb6c0c55a28f6df8eba5e39fCAS | 18372493PubMed |
[4] Satterwhite CL, Tian LH, Braxton J, Weinstock H. Chlamydia prevalence among women and men entering the National Job Training Program: United States, 2003–2007. Sex Transm Dis 2010; 37 63–7.
| Chlamydia prevalence among women and men entering the National Job Training Program: United States, 2003–2007.Crossref | GoogleScholarGoogle Scholar | 19801962PubMed |
[5] Satterwhite CL, Grier L, Patzer R, Weinstock H, Howards PP, Kleinbaum D. Chlamydia positivity trends among women attending family planning clinics: United States, 2004–2008. Sex Transm Dis 2011; 38 989–94.
| Chlamydia positivity trends among women attending family planning clinics: United States, 2004–2008.Crossref | GoogleScholarGoogle Scholar | 21992972PubMed |
[6] Cleves M, Tosetto A. Logistic regression when binary outcome is measured with uncertainty. J Med Virology 2000; 55 20–3.
[7] National Chlamydia Coalition. Research Briefs (2010 Series, No. 1). Developments in STD Screening: Chlamydia testing. National Chlamydia Coalition; 2010. Available online at: http://www.prevent.org/data/files/ncc/research%20brief%201%20std%20testing.pdf [verified 1 August 2015].
[8] Gen-Probe. Package insert. PACE 2 Chlamydia trachomatis (501677EN Rev.C). San Diego: Gen-Probe; 2011.
[9] Gen-Probe. Package insert. PACE 2C Chlamydia trachomatis and Neisseria gonorrhoeae (501685EN Rev.C). San Diego: Gen-Probe; 2011.
[10] Digene Corporation. Package insert. hc2 CT-ID DNA Test Version 2.0. Gaithersburg: Digene Corporation; 2007.
[11] Martin DH, Nsuami M, Schachter J, Hook EW, Ferrero D, Quinn TC, Gaydos C. Use of multiple nucleic acid amplification tests to define the infected-patient “gold standard” in clinical trials of new diagnostic tests for Chlamydia trachomatis infections. J Clin Microbiol 2004; 42 4749–58.
| Use of multiple nucleic acid amplification tests to define the infected-patient “gold standard” in clinical trials of new diagnostic tests for Chlamydia trachomatis infections.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXpvFKqu7Y%3D&md5=dc94ea2dff74019e74da8d65dc7190e6CAS | 15472336PubMed |
[12] Fine D, Dicker L, Mosure D, Berman S. Increasing chlamydia positivity in women screened in family planning clinics: do we know why? Sex Transm Dis 2008; 35 47–52.
| Increasing chlamydia positivity in women screened in family planning clinics: do we know why?Crossref | GoogleScholarGoogle Scholar | 17700377PubMed |
[13] van den Broek IV, van Bergen JE, Brouwers EE, Fennema JS, Gotz HM, Hoebe CJ, et al Effectiveness of yearly, register based screening for chlamydia in the Netherlands: controlled trial with randomised stepped wedge implementation. BMJ 2012; 345 345
| Effectiveness of yearly, register based screening for chlamydia in the Netherlands: controlled trial with randomised stepped wedge implementation.Crossref | GoogleScholarGoogle Scholar |
[14] Peterman TA, Newman DR, Goldberg M, Anschuetz GL, Salmon M, Satterwhite CL, Berman SM. Screening male prisoners for Chlamydia trachomatis: impact on test positivity among women from their neighborhoods who were tested in family planning clinics. Sex Transm Dis 2009; 36 425–9.
| Screening male prisoners for Chlamydia trachomatis: impact on test positivity among women from their neighborhoods who were tested in family planning clinics.Crossref | GoogleScholarGoogle Scholar | 19525892PubMed |
[15] Golden MR, Whittington WL, Handsfield HH, Hughes JP, Stamm WE, Hogben M, et al Effect of expedited treatment of sex partners on recurrent or persistent gonorrhea or chlamydial infection. N Engl J Med 2005; 352 676–85.
| Effect of expedited treatment of sex partners on recurrent or persistent gonorrhea or chlamydial infection.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXhtlGhtLg%3D&md5=91cd85c8fff19da7db90e5f3cdcad4b0CAS | 15716561PubMed |
