Sexually Transmitted Disease Surveillance 1995

Division of STD Prevention

September 1996

U.S. Department of Health and Human Services 
Public Health Service 
Centers for Disease Control and Prevention  
National Center for HIV, STD, and TB Prevention 
Division of STD Prevention 
Atlanta, Georgia 30333

Copyright Information 

All material contained in this report is in the public domain and may be
used and reprinted without special permission; citation to source, however,
is appreciated.

Suggested Citation

Division of STD Prevention. Sexually Transmitted Disease Surveillance,
1995. U.S. Department of Health and Human Services, Public Health Service.
Atlanta: Centers for Disease Control and Prevention, September 1996.

Copies can be obtained from Information Technology and Services Office,
National Center for HIV, STD, and TB Prevention, Centers for Disease
Control and Prevention, 1600 Clifton Road, Mailstop E-06, Atlanta, Georgia
30333 or by telephone at (404) 639-1819.

The reports for 1993 through 1995 are now available electronically on CDC
WONDER. For information about registering for CDC WONDER, please contact
CDC's Information Resource Management Office at (404) 332-4569. These
reports are also available from the Internet via the CDC home page address
http://www.cdc.gov.


                    Sources and Limitations of Data 

CDC Surveillance Data

The information in this document was based on cases of sexually transmitted
diseases (STDs) reported to the Division of STD Prevention (DSTDP), Centers
for Disease Control and Prevention (CDC), by the STD control programs and
health departments in the 50 states, the District of Columbia, selected
cities, U.S. dependencies and possessions, and independent nations in free
association with the United States. Included among the dependencies,
possessions, and independent nations are Guam, Puerto Rico, and the Virgin
Islands. These are referred to as "outlying areas of the U.S." in the
tables. At present, STD data are submitted to CDC on a variety of hardcopy
summary reports (monthly, quarterly, and annually) and electronically
either in summary or individual case-listed format. DSTDP is currently
working on converting from hardcopy reporting of summary data to electronic
submission of line-listed (i.e., case-specific) data. The data used in this
report are predominantly based on the summary hardcopy reports. Monthly
reports included summary data for syphilis by county and state. Quarterly
reports included summary data for syphilis, gonorrhea, chlamydia, and other
STDs by gender and source of report (STD clinic or non-STD clinic) for the
50 states, 64 large cities (most with a population of >200,000), and
outlying areas of the United States. Annual reports included summary data
for syphilis and gonorrhea by age, race, and gender for the 50 states and
six large cities. In addition, data on antimicrobial susceptibility in
Neisseria gonorrhoeae were collected through the Gonococcal Isolate
Surveillance Project (GISP), a sentinel system of 25 STD clinics (1995) and
five laboratories located throughout the United States. Provisional data on
syphilis and gonorrhea reported to CDC weekly by states for inclusion in
the Morbidity and Mortality Weekly Report were not included in this
document.

Areas differ in their ability to resolve differences in total cases derived
from hardcopy monthly, quarterly, and annual reports (as well as
electronically submitted case-listed data). Thus, depending on the database
used, there may be discrepancies in total cases in the tables and figures.
In most instances, these discrepancies are less than 5% of total reported
cases and have minimal impact on national total cases and rates. However,
for a specific area, the discrepancies may be larger.

Reports and corrections sent to CDC through March 31, 1996 have been
included. Those received after this date will appear in subsequent issues.
The data in the tables and figures in this document supersede those in all
earlier publications.

Population Denominators and Rate Calculations

Crude incidence rates (new cases/population) were calculated on an annual
basis per 100,000 population. For the United States, rates were calculated
by using Bureau of the Census population estimates for 1981 through 1989
(Bureau of the Census; United States Population Estimates by Age, Sex and
Race: 1980-1989 [Series P-25, No. 1045]; Washington: US Government Printing
Office, 1990; and United States Population Estimates by Age, Sex and Race:
1989 [Series P-25, No. 1057]; Washington: US Government Printing Office,
1990). Rates for states and counties were calculated by using published
intercensal estimates based on Bureau of the Census population estimates
for 1980-1989 (Irwin R; 1980-1989 Intercensal Population Estimates by Race,
Sex, and Age; Alexandria, [VA]: Demo-Detail, 1992; machine-readable data
file). Rates for 1990 were calculated using population data from the 1990
census (Census of Population and Housing, 1990: Summary Tape File 1 (All
States) [machine-readable file]; Washington: Bureau of the Census, 1991),
which included information on area (county, state), age (5-year age
groups), race (white, black, Asian/Pacific Islander, American Indian/Alaska
Native) and ethnicity (Hispanic). Rates for 1991-1995 were updated from
previous issues of this report using postcensal population estimates for
1991-1995 based on the Bureau of the Census data (Irwin R; 1991-1995
Postcensal Population Estimates by Race, Sex, and Age; Alexandria, [VA]:
Demo-Detail, 1996; machine-readable data file).

Many cities do not have a separate health jurisdiction that collects and
reports cases of STDs. For these cities, case numbers and crude incidence
rates are equal to those of the county or counties in which the city is
located. For the remaining cities, incidence rates were calculated by using
population estimates based on the Bureau of the Census (Irwin R, see above)
and a marketing survey (Market Statistics, Inc; Sales and Marketing
Management; New York: Bill Communications, Inc, August 1989). Population
estimates for areas outside the United States were obtained from the Bureau
of the Census (Bureau of the Census; population estimates for Puerto Rico
and the outlying areas: 1980 to 1988; Current Population Reports [Series
P-25, No. 1049]; Washington: US Government Printing Office, 1989).
Population estimates for the outlying areas for 1989-1995 were obtained
directly from the health departments in these areas. For Guam and Virgin
Islands, rates for 1992-1995 were based on 1992 population estimates
because more current estimates were unavailable.

The percentage of cases for which race/ethnicity and age were unknown or
unspecified differed considerably, depending on year and area. In 1983 and
1984, up to 25% of total U.S. cases were in this category. In these years,
states were excluded from analysis if race/ethnicity and age were not
reported for the majority of cases. Otherwise, if race/ethnicity or age was
unknown or unspecified, cases were distributed according to the cases for
which these data were available. In this edition, 1981 through 1995 age- 
and race-specific rates (for gonorrhea and syphilis in the National
Profile, Special Focus Profiles and Detailed Tables) are calculated from
estimates based on this redistribution. 

Rates of congenital syphilis for 1989-94 were calculated using live births
from the National Center for Health Statistics (NCHS) (Vital Statistics:
Natality Tapes 1989-1992 or Vital Statistics Reports, United States 1995,
Vol. 43 No.13 -- Natality). Rates for 1995 were calculated using live
births for 1994. Rates before 1989 were calculated using published live
birth data (NCHS; Vital Statistics Report, United States, 1988 [Vol.1 --
Natality]).

Case Definitions and Reporting Practices

Although most areas generally adhere to the case definitions for STDs found
in Case Definitions for Public Health Surveillance (MMWR 1990;39(RR-13):
1-43), there are significant differences between individual areas in case
definitions as well as in the policies and systems for collecting
surveillance data. Thus, comparisons of case numbers and rates between
areas should be interpreted with caution. However, since case definitions
and surveillance activities within a given area remain relatively stable,
trends should be minimally affected. In many areas, reporting from publicly
supported institutions (e.g., STD clinics) was more complete than from
other sources (e.g., private practitioners). Thus, the trends may not be
representative of all segments of the population. Military cases are not
reported as a separate category.

Reporting of Congenital Syphilis Cases

In 1989, a new surveillance case definition for congenital syphilis was
introduced. The new case definition has greater sensitivity than the former
definition. In addition, many areas greatly enhanced active case finding
for congenital syphilis during this time. For these reasons, the number of
reported cases increased dramatically during 1989-1991. As is true of any
change, a period of transition during which trends cannot be clearly
interpreted has resulted; however, all reporting areas had implemented the
new case definition for reporting all cases of congenital syphilis after
January 1, 1992. Therefore, the reliability of trends is expected to have
stabilized after this date.

In addition to changing the case definition, CDC introduced a new data
collection form (CDC 73.126) in 1990. Beginning with 1995, the data
collected on this form are used for reporting congenital syphilis reported
cases and associated rates. This form collects individual case information
which allows more thorough analysis of cases. For the purposes of these
analyses if either race or ethnicity question was answered, the case was
included. For example, if "White" race was marked, but ethnicity was left
blank, the individual was counted as "non-Hispanic White".

Reporting of Gonorrhea Cases

In 1994, Georgia reported gonorrhea cases to CDC for only part of a year.
Therefore, Georgia cases and population were excluded from gonorrhea
figures and tables for 1994. The city of Atlanta was also excluded from
city figures and tables for 1994.

Reporting of Chlamydia Cases

In 1995, only the states of Alaska and New York did not yet have laws or
policies for uniform reporting of Chlamydia trachomatis cases. (Effective
February 1996, Alaska initiated mandatory reporting of Chlamydia.) These
states did not report cases to the CDC or their reported cases and rates
were much lower than expected. Population denominators from these areas
were excluded when calculating U.S. total rates. Trends in many areas were
more representative of increases in reporting of cases rather than actual
trends in disease. Cases and rates of chlamydia reported in gender-specific
tables are underestimated due to substantial numbers of cases with unknown
gender. Despite problems with under-reporting, we feel it is important to
publish the data to emphasize the large numbers of cases of chlamydia being
detected in the United States. As areas develop chlamydia prevention and
control programs, including improved surveillance systems to monitor
trends, the data should improve and become more representative of true
trends in disease.

Chlamydia testing data for the area-specific figures in the Special Focus
Profiles section were published with permission from the Region X Chlamydia
Project. Chlamydia test positivity was calculated by dividing the number of
women testing positive for chlamydia (numerator) by the total number of
women tested for chlamydia (denominator) and was expressed as a percentage.
While not common, the denominator may contain multiple tests from the same
individual if that person was tested more than once during a year. Various
chlamydia test methods were used and no adjustments of test positivity were
made based on test type. Chlamydia testing data for region- and
state-specific figures in the Special Focus Profiles section were published
with permission from the PHS Regional Infertility Prevention Programs,
selected state STD prevention programs, and the Job Corps, U.S. Department
of Labor.

Other Data Sources

The information on the number of initial visits to private practitioners'
offices for sexually transmitted diseases was based on analysis of data
from the National Disease and Therapeutic Index (NDTI) (machine-readable
files or summary statistics for years 1966-1995). For more information on
this database, see IMS America, Ltd; National Disease and Therapeutic Index
(NDTI): Diagnosis April 1989-December 1995; Plymouth Meeting (PA): IMS
America, Ltd, 1996.

The information on patients hospitalized for pelvic inflammatory disease or
ectopic pregnancy was based on analysis of data from the National Hospital
Discharge Survey (machine-readable files for years 1980-1993; 1994 and 1995
unavailable for this report), an ongoing nationwide sample survey of
short-stay hospitals in the United States, conducted by the National Center
for Health Statistics. For more information, see Graves EJ; 1988 Summary:
National Hospital Discharge Survey; Advance data No. 185; Hyattsville (MD):
National Center for Health Statistics, 1990. The National Hospital
Ambulatory Medical Care Survey (NHAMCS) (machine-readable file for 1993)
was used to obtain estimates of number of emergency room visits for pelvic
inflammatory disease among women ages 15 to 44. The estimates generated
using these data sources (NHDS and NHAMCS) are based on statistical surveys
and therefore have sampling variability associated with the estimates.

Healthy People Year 2000 Revisions

In 1995, the Healthy People year 2000 objectives were revised (1).
Therefore, in this year's report, the year 2000 objectives were revised as
follows: primary and secondary syphilis -- 10 per 100,000 population to 4;
congenital syphilis -- 50 per 100,000 livebirths to 40; and gonorrhea --
225 per 100,000 population to 100.

---------------
(1) Department of Health and Human Services. Healthy People 2000: Midcourse
    Review and 1995 Revisions. U.S. Department of Health and Human
    Services, Public Health Service. U.S. Government Printing Office,
    Washington, D.C., 1995.

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