Asymptomatic sexually transmitted diseases: the case for screening

Abstract

Background

The United States has the highest prevalence of sexually transmitted diseases in the developed world. Control strategies should address the most frequent reasons why curable sexually transmitted diseases are not treated.

Methods

We approached 1,631 persons ages 18–29 in various sites and offered them screening for gonorrhea and chlamydial infection and surveys regarding past genitourinary symptoms. For those with past symptoms we abstracted medical records or conducted additional interviews. From these data we estimated the total number of persons who had gonorrhea or chlamydial infections in the previous year, the proportion treated, and the primary reasons for nontreatment.

Results

The prevalence of gonorrhea was 2.3% and that of chlamydial infection was 10.1%. We estimate that 45 and 77% of all cases of gonorrhea and chlamydial infection, respectively, were never symptomatic and that 86 and 95% of untreated cases of gonorrhea and chlamydial infection, respectively, were untreated because they were never symptomatic. The remaining 14 and 5% of untreated cases of gonorrhea and chlamydia, respectively, were not treated because persons did not receive medical care for symptoms.

Conclusions

The primary reason that gonorrhea and chlamydial infections are untreated is that infected persons never have symptoms. The most effective method to control these sexually transmitted diseases is routine screening at high-volume sites.

Introduction

The Institute of Medicine report, The Hidden Epidemic, documented that control of sexually transmitted diseases (STDs) has been relatively neglected in America, leaving the United States with the highest prevalence of STDs in the developed world [1]. The direct and indirect health care costs related to STDs (excluding HIV) are estimated to be $10 billion per year, which is greater than the estimated costs for HIV infection [1]. The most common bacterial STDs in the United States are infection with Chlamydia trachomatis and Neisseria gonorrhoeae [1]. Laboratory and epidemiologic research has demonstrated that many bacterial STDs, including gonorrhea and possibly chlamydial infection, facilitate HIV transmission [2]. Based on this data the U.S. Centers for Disease Control and Prevention recommends enhanced diagnosis and treatment of STDs as a means to prevent HIV infection [3]. The opportunities for enhanced diagnosis and treatment have recently been expanded through sensitive urine-based screening tests and single-dose oral therapies [4], [5], [6], [7].

Although many persons with STDs seek and receive appropriate medical care for their infections, many do not. STDs that are unrecognized or untreated for other reasons then provide a reservoir for transmission to others. Neither the magnitude of the problem of untreated STDs nor the primary reason why STDs are untreated is well understood. Defining the frequency of and reasons why some STDs remain untreated can guide future efforts to control STDs and prevent HIV infection.

In broad terms, there are three possible reasons why persons with curable STDs may not be appropriately treated for their infections: (1) they may not have symptoms (or may not recognize symptoms), (2) they may recognize symptoms, but not receive medical care, either because they do not believe medical treatment is needed or because medical treatment is not readily available, or (3) they may receive medical care, but the STD diagnosis is not made or the proper treatment is not provided. To maximize the number of currently untreated infected persons who could be treated in an enhanced STD control program, it is important first to determine the approximate proportion of infected persons for whom each of these three barriers to treatment occurs. If a large proportion of persons with STDs do not have or recognize symptoms, then interventions should focus on screening of asymptomatic persons. If a large proportion of persons with STDs recognize symptoms but do not receive medical care, then interventions should focus on improving access to and utilization of medical care. If a large proportion of persons with STDs receive medical care for symptoms of these STDs but are not properly treated, then interventions should focus on improving diagnostic and treatment practices of existing medical providers. We collected data to estimate the relative frequency of these reasons for nontreatment among young adults in New Orleans, a high-incidence area.