Presented by Lizzi Torrone, MSPH, PhD, Epidemiologist, Division of STD Prevention, CDC, at the 2012 National Chlamydia Coalition meeting.

1. Chlamydia Trends:
What We Do and Don’t Know
Lizzi Torrone
Epidemiologist
Division of STD Prevention
National Chlamydia Coalition
January 26, 2012
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
Division of STD Prevention

3. Chlamydia—Rates by Sex,
United States, 1990–2010
Rate (per 100,000 population)
750
Women
625
500
375 Total
250
Men
125
0
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010
Year
NOTE: As of January 2000, all 50 states and the District of Columbia have regulations that require the
reporting of chlamydia cases.

4. Chlamydia—Rates by Age and Sex,
United States, 2010
Men Rate (per 100,000 population) Women
3,700 2,960 2,220 1,480 740 0 0 740 1,480 2,220 2,960 3,700
Age
774.3 15–19 3,378.2
1,187.0 20–24 3,407.9
598.0 25–29 1,236.1
309.0 30–34 530.9
153.2 35–39 220.1
91.3 40–44 94.7
39.3 45–54 32.8
10.9 55–64 9.3
2.8 65+ 2.1
233.7 Total 610.6

5. Chlamydia—Percentage of Reported Cases by Sex and
Selected Reporting Sources, United States, 2010
Percentage
40
Private Physician/HMO*
35 STD Clinic
Other HD* Clinic
30 Family Planning Clinic
25 Emergency Room
20
15
10
5
0
Men Women
*HMO = health maintenance organization; HD = health department.
NOTE: These categories represent 72.5% of cases with a known reporting source. Of all cases, 11.6% had a
missing or unknown reporting source.

6. What do chlamydia case report data tell us?
 Chlamydia is the most commonly reported nationally
notifiable disease.
 Chlamydia is most commonly diagnosed among young
females.
 Many females are diagnosed in private healthcare
settings.

7. What do chlamydia case report data NOT tell us?
 The incidence and prevalence of chlamydia.
 Duration of infection is unknown
 Doesn’t account for changes in
• Screening coverage
• Test technology used
• Empiric treatment
• Reporting practices

8. Chlamydia Screening Coverage* Trends
(Women Aged 16-20 and 21-24 years, HEDIS)
Percentage
100
80 Medicaid (21-24 yos)
Medicaid (16-20 yos)
60
40
20
0
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
*Among women enrolled in commercial or Medicaid plans who had a visit where they were determined to be sexually active
The State of Healthcare Quality, 2011: http://www.ncqa.org/LinkClick.aspx?fileticket=FpMqqpADPo8%3d&tabid=836

9. What do chlamydia case report data NOT tell us?
 The incidence and prevalence of chlamydia.
 Duration of infection is unknown
 Doesn’t account for changes in
• Screening coverage
• Test technology used
• Empiric treatment
• Reporting practices

10. Percentage of Nucleic Acid Amplification Tests (NAATs) Used
Among Women, Infertility Prevention Project, 2000–2010
Percentage
100
80
60
40
20
0
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

11. What do chlamydia case report data NOT tell us?
 The incidence and prevalence of chlamydia.
 Duration of infection is unknown
 Doesn’t account for changes in
• Screening coverage
• Test technology used
• Empiric treatment
• Reporting practices

12. What do we know about trends in Chlamydia?
 Case reports are increasing, but…
 Likely reflects increased screening and use of NAATs

13. After analyzing data at the clinic level to account for
unmeasured factors between clinics (e.g., screening
practices), positivity remained stable from 2004–2008.
Limitation: Can’t account for changes within clinics over
time (e,g., demographic shifts in who goes to the clinic)

14. Among both women (19%) and men (8%) aged 16-24
years entering the national job training
program, chlamydia prevalence declined significantly
from 2003–2007.
Limitation: May not be generalizable and
population entering program may change over time

15. epub, Dec 2012
In nationally representative surveys from 1999–2008,
prevalence decreased 40% among men and women
aged 14–39 years and prevalence remained stable
among women aged 14–25 years.
Limitation: Small sample sizes and low prevalence
limit ability to monitor trends in subgroups

16. What do we know about trends in chlamydia?
 Case reports are increasing, but…
 Likely reflects increasing screening and use of NAATs
 Positivity and prevalence estimates suggest stable or
decreasing morbidity, but…
 Current national data sources have limitations

17. What don’t we know about trends in chlamydia?
What opportunities do we have?
 Increase screening coverage
 Particularly among adolescents
 Within the context of a changing healthcare environment
 Improve chlamydia surveillance
 Limitations of current national data sources
 Consider different metrics and data sources

18. Acknowledgements
 Jim Braxton
 LaZetta Grier
 Rob Nelson
 Catherine Satterwhite
 Hillard Weinstock

19. Thank you!
ETorrone@cdc.gov
For more information please contact Centers for Disease Control and Prevention
1600 Clifton Road NE, Atlanta, GA 30333
Telephone: 1-800-CDC-INFO (232-4636)/TTY: 1-888-232-6348
E-mail: cdcinfo@cdc.gov Web: http://www.cdc.gov
The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the
Centers for Disease Control and Prevention.
National Center for HIV/AIDS, Viral Hepatitis, STD , and TB Prevention
Division of STD Prevention