Sexually Transmitted Disease Surveillance 1994

Division of STD Prevention

September 1995

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 (proposed)
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,
1994. U.S. Department of Health and Human Services, Public Health Service.
Atlanta: Centers for Disease Control and Prevention, September 1995.

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

Both the 1993 and 1994 reports 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.

                    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, and U.S. dependencies and possessions, and
independent nations in free association with the United States. (1)
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. Data were received as summary
statistics monthly, quarterly, and annually. Monthly reports included
summary data for syphilis by county and state. Quarterly reports included
summary data for syphilis, gonorrhea, 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 24 STD clinics (1994) and 5 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 monthly, quarterly, and annual reports. 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 February 28, 1995, 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

     Incidence rates 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 1991-1992 were updated from previous issues
of this report using postcensal population estimates for 1991-1992 based on
the Bureau of the Census data (Irwin R; 1991-1992 Postcensal Population
Estimates by Race, Sex, and Age; Alexandria, [VA]: Demo-Detail, 1994;
machine-readable data file). Rates for 1993 and 1994 were calculated using
the postcensal 1992 population denominators cited previously.
     Many cities do not have a separate health jurisdiction that collects
and reports cases of STD. For these cities, case numbers and 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 1989-1992 were obtained
directly from the health departments in these areas. Rates in these areas
for 1992-1994 used 1992 population estimates.
     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 1994
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 were calculated using live births from
the National Center for Health Statistics (NCHS) (Vital Statistics:
Natality Tapes, 1989-1991). 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 STD
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. This form collects individual case
information and allows more thorough analysis of cases. By 1992, most areas
had implemented this form. Race and ethnicity rates for congenital syphilis
have been calculated for 1992-1994 using these data. 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. The city of Atlanta has also been excluded from city
figures and tables. In past years, Georgia has been among the states
reporting the highest gonorrhea rates. Approximately 30,000 gonorrhea cases
were expected to be reported from Georgia for 1994. If these cases had been
included, there would have been very little change or a small increase in
the national rate between 1993 and 1994.

Reporting of Chlamydia Cases

     Some areas do not yet have laws or policies for uniform reporting of
Chlamydia trachomatis cases. 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. Despite the
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.

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 for years 1966-1993). NDTI data were not obtained
for 1994. For more information on this database, see IMS America, Ltd;
National Disease and Therapeutic Index (NDTI): Diagnosis April 1989-March
1990; Plymouth Meeting (PA): IMS America, Ltd, 1990.
     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), an ongoing nationwide sample survey of short-stay hospitals in
the United States, conducted by the (1) 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.

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