Surveillance and Data

Introduction

The Centers for Disease Control and Prevention (CDC) and the Office of Population Affairs (OPA) initiated a chlamydia demonstration project in the Northwestern region of the United States, Public Health Service (PHS) Region X. In 1993, this demonstration project was expanded to include PHS Regions III, VII and VIII, and in 1995 services were implemented in the remaining PHS regions (I, II, IV, V, VI, IX). The projects are funded through the Regional Infertility Prevention Projects legislation, which aims to reduce the costly and destructive sequelae of chlamydia and other sexually transmitted diseases on the reproductive health of women.

Sources of Data ^[1]

All regional projects, in collaboration with state STD control and family planning programs, report their chlamydia positivity data to the regional database (housed at JSI Research & Training Institute in Denver, for Region VIII) which is then forwarded to CDC. For some of the programs in Region VIII, Federally-funded programs supplement existing local and state funded testing programs. These publicly funded programs support chlamydia screening primarily in family planning clinics, but also in some STD clinics, jails and juvenile detention centers, Indian Health Service, and other sites. The PHS Region VIII referred to in the data tables are the following: Colorado, Montana, North Dakota, South Dakota, Utah and Wyoming.

Descriptions of the Data Tables

The data tables report positivity rates by age group and certain client characteristics (clinical signs reported by clinicians at exam and risk history reported by client). These are done at the comprehensive level of state (all agencies and gender) and are reported in total.

There are no Gonorrhea Results for North Dakota and South Dakota. Gonorrhea data for these states are not reported to the regional database.

Data Limitations

The interpretation of chlamydia data is compounded by several factors.

1. First, case reports and prevalence data result from the use of several different types of diagnostic tests for chlamydia infection (e.g. DNA probe assay, DNA amplification); these tests vary in their sensitivity and specificity.
2. Second, chlamydia positivity among women attending clinics is an estimate of prevalence; it is not true prevalence. Crude positivity may include those women who are tested two or more times during a single year. Comparisons of positivity with prevalence have shown that in family planning clinics, positivity is generally similar to or slightly higher than prevalence, and in STD clinics, positivity is somewhat lower than prevalence; however, these differences are usually small, with the relative difference <10%. ^[2]
3. Third, while nearly all family planning clinics perform universal screening of sexually active women <20 years of age, and most clinics do so among women <25 years of age, some selective screening is performed among women 20-24 years of age and some level of screening is frequently performed among women >25 years of age.
4. Fourth, while monitoring prevalence among persons seeking care at clinics provides important information on certain segments of the population, these data cannot be generalized to the population as a whole. ^[1]
5. Fifth, the data that are reported into the regional database do not reflect all the screening and testing being performed across PHS Region VIII.
6. Lastly, the enhanced data elements (clinical signs and risk history) and gonorrhea data only reflect a certain portion of records reported to the regional database.

 

* Content provided in collaboration with the Family Planning Council