STD Screening in HIV Clinics: Value and Implications
Thomas Farley, MD MPH
Tulane University
Deborah Cohen, MD MPH
RAND Corporation
Background (1)Sexual Activity in HIV+ Persons
Much emphasis in U.S. response to the AIDS epidemic is on identification, referral, and treatment of HIV-infected persons; however...
…many HIV-infected persons continue to be sexually active after diagnosis and during treatment
HIV prevention strategies should include intensive counseling to HIV-infected persons who continue to practice unprotected sex
Identification of these persons needed
Background (2)STDs in HIV+ Persons
Curable STDs facilitate the spread of HIV infection
Diagnosis and treatment of curable STDs in HIV-infected persons helps prevent HIV infection in partners, even when infected persons continue unprotected sex
STD screening and treatment in HIV clinics is essential part of overall strategy for HIV prevention
Still, routine STD screening does not occur in most HIV clinics
CDC Guidelines:“HIV Prevention Through Early Detection and
Treatment of Other Sexually Transmitted Diseases”*
“Persons already infected with HIV should be screened routinely for STDs…including gonorrhea, chlamydial infection, syphilis, and -- among women -- trichomoniasis… Screening frequency should be at least yearly if any potential risk exists for STD acquisition. It should be performed more frequently if any incident STDs are detected by symptoms or screening. These services should be provided as part of and at the site of routine, quality HIV care. “
*MMWR 1998;47(RR12):1-24.
Background (3)STD Screening in HIV+ Clinic in New Orleans
In October 1998, HIV/STD Programs in Louisiana began offering routine gonorrhea and chlamydia screening to HIV Outpatient Program (HOP) in New Orleans
Screening by urine-based Ligase Chain Reaction (LCR) test
Clinic: 2,500 active patients, 12,000 visits per year; 22% CD4 count < 200
Protocol routine urine screening at initial and biannual visits; but up to provider to order tests
Objectives
To determine the prevalence of gonorrhea and chlamydia and secular trends in prevalence among HIV-infected persons in care
To assess relationship between STD prevalence in HIV-infected persons and STD rates in general population
To assess value of continued routine STD screening in HIV clinics
Methods Analyzed data from gonorrhea/chlamydia laboratory slips from
October 1998 - June 2001
Obtained data on number of visits and number of active patients from HOP clinic billing database
Compared HOP clinic results to screening of convenience samples of persons 18-29 in New Orleans as part of unrelated study
Compared HOP results to city-wide trends in gonorrhea and chlamydia obtained from Louisiana Office of Public Health
Relationship Between Visits and TestsHIV Outpatient Program, New Orleans,
October 1998- June 2001
• 34,837 visits – Includes initial, routine follow-up and problem-
focused visits
• 2,629 tests - 7.5% of visits
• Type for visit not available on lab test slip
Percentage of Active Patients TestedHIV Outpatient Program, New Orleans, June 2000-May 2001
25%176708White Males
33%8372,555Total
92
964
707
Patients*
White Females
Black Males
Black Females
45%41
31%297
41%292
% TestedTested*
* Unduplicated count for 12-month period
Prevalence of STDs HIV Outpatient Program, New Orleans, 1998-2001
Tested Positive % Positive
Gonorrhea 2,629 46 1.7%
Chlamydia 2,629 56 2.1%
Prevention Benefit of STD Screening
• Based on mathematical model* of the effect of STD treatment on HIV transmission:– Treatment of 46 HIV-infected persons with
gonorrhea prevents 7 cases of infection in partners
– Treatment of 56 HIV-infected persons with chlamydia prevents 12 cases of infection in partners
– Total: prevention of HIV/AIDS in 19 persons
* Adapted from Chesson and Pinkerton. JAIDS 2000;24:48-56
Prevalence of STDs by Race and SexHIV Outpatient Program, New Orleans, 1998-2001
0.0%
0.5%
1.0%
1.5%
2.0%
2.5%
3.0%
3.5%
4.0%
Gonorrhea Chlamydia
Pre
vale
nce
(%)
Black Female White Female Black Male White Male
Prevalence of STDs by Age GroupHIV Outpatient Program, New Orleans, 1998-2001
0.0%
1.0%
2.0%
3.0%
4.0%
5.0%
6.0%
7.0%
8.0%
9.0%
10.0%
15-19 20-24 25-29 30-34 35-39 40-44 45-49 > 50
Age Group
Pre
vale
nce
(%)
Gonorrhea Chlamydia
Convenience Sample to Estimate Population Prevalence of STDs
• Persons offered urine-based screening for gonorrhea, chlamydia, and HIV
• May 1999 – July 2000• Sampled from 10 sites in New Orleans, including:
– Hospital emergency rooms and walk-in clinics– Dental clinic– Colleges– Facility for homeless youth– Vo-tech school
• Excluded persons seeking care for genitourinary symptoms
• Age 18-29 only; 82% Black, 14% White• N=1,610
Gonorrhea Prevalence vs Convenience Sample of General Population
New Orleans
0.0%
1.0%
2.0%
3.0%
4.0%
5.0%
6.0%
15-19 20-24 25-29 30-34 35-39 40-44 45-49 > 50
Age Group
Gon
orrh
ea P
reva
lenc
e (%
)
HOP Population
Chlamydia Prevalence vs. Convenience Sample of General Population
New Orleans
0.0%
2.0%
4.0%
6.0%
8.0%
10.0%
12.0%
14.0%
15-19 20-24 25-29 30-34 35-39 40-44 45-49 > 50
Age Group
Chl
amyd
ia P
reva
lenc
e (%
)
HOP Population
Secular Trends in PrevalenceHIV Outpatient Program, New Orleans, 1998-2001
0.0%
0.5%
1.0%
1.5%
2.0%
2.5%
3.0%
3.5%
1998 1999 2000 2001
Year
Pre
vale
nce
(%)
Gonorrhea Chlamydia
Trends in Prevalence Among Persons < 30HIV Outpatient Program, New Orleans, 1998-2001
0.0%
1.0%
2.0%
3.0%
4.0%
5.0%
6.0%
7.0%
8.0%
9.0%
1998 1999 2000 2001
Year
Pre
vale
nce
(%)
Gonorrhea Chlamydia
Trends in Prevalence Among Persons > 30HIV Outpatient Program, New Orleans, 1998-2001
0.0%
0.2%
0.4%
0.6%
0.8%
1.0%
1.2%
1.4%
1.6%
1998 1999 2000 2001
Year
Pre
vale
nce
(%)
Gonorrhea Chlamydia
Comparison of Trends in Gonorrhea HOP Prevalence vs. Surveillance Data
New Orleans, 1998-2001
0.0%
0.5%
1.0%
1.5%
2.0%
2.5%
3.0%
1998 1999 2000 2001
Year
Pre
va
len
ce
at
HO
P
0
100
200
300
400
500
600
700
800
Ca
se
s p
er
10
0,0
00
in N
ew
O
rle
an
s
HOP New Orleans
Comparison of Trends in ChlamydiaHOP Prevalence vs. Surveillance Data
New Orleans, 1998-2001
0.0%
0.5%
1.0%
1.5%
2.0%
2.5%
3.0%
3.5%
1998 1999 2000 2001
Year
Pre
va
len
ce
at
HO
P
0
100
200
300
400
500
600
700
800
900
1000
Ca
se
s p
er
10
0,0
00
in N
ew
O
rle
an
s
HOP New Orleans
Summary
• Among HIV-infected persons in care, 1.7% had gonorrhea and 2.1% had chlamydia
• Treatment of these infections prevented an estimated 19 cases of HIV/AIDS in partners
• STD prevalence did not vary substantially by race or sex, but was higher in persons under age 30
• STD prevalence was similar to that of general population
• STD prevalence varied over time in parallel with population STD rates
Conclusions
• Routine STD screening in HIV clinics is feasible• Screening and treatment for gonorrhea and
chlamydia in HIV clinics prevents substantial number of HIV infections, even when prevalence is ~2%.
• HIV-infected persons in care continue to practice high risk sexual behavior, probably at about the same level and in the same sexual networks as the general population
• STD screening in HIV clinics identifies persons with curable STDs who can be treated and intensively counseled to prevent transmission of HIV to others
Recommendations
• Routine STD screening should be established in all HIV clinics, following CDC guidelines
• Intensive counseling and partner notification should be implemented for HIV-positive persons in care who have STDs
• Prevention of STDs in the general population should be considered an HIV prevention strategy, as it should lead to lower STD rates in HIV-infected persons and thus less HIV transmission