Volume 14, Issue 2, Spring/Summer 2002
STD Research:
Promising opportunities to improve public health
Termed the "Hidden Epidemic" in a 1996 Institute of Medicine report, sexually transmitted diseases (STDs) such as chlamydia and gonorrhea are an under-recognized problem in the U.S. According to CHS investigator Delia Scholes, STDs have yet to become a major health priority in the U.S., even though they affect about 15 million Americans each year and, if left untreated, can lead to such serious health consequences as infertility, pelvic inflammatory disease, and cancer. The lack of awareness surrounding STDs is especially frustrating given the potential that exists to curtail this epidemic. "STDs offer a lot of opportunity from the public health standpoint. They are common, costly and preventable; many are curable. In spite of that, the U.S. has lagged far behind other industrialized nations in confronting this problem," says Scholes.
Why do STDs remain the hidden American epidemic? First, these infections are often asymptomatic, especially in women. Second, the long lag time between infection and the development of a more serious complication such as infertility tends to obscure the connection between the two events. Third, the stigma associated with discussing STDs in the U.S. inhibits awareness, open dialogue, and unified action. In contrast, over the past few decades other industrialized nations have been successful in tackling their STD problems, largely through systematic efforts beginning at the national level.
CHS investigator Delia Scholes has been doing her part in the past 15 years to bring STD prevention and early detection into the open. Much of her work has focused on Chlamydia trachomatis, the most common sexually transmitted bacterial pathogen in the U.S. Cervical chlamydial infection is largely asymptomatic in women and, if left untreated, can lead to pelvic inflammatory disease (PID). Characterized by scarring of the fallopian tubes and endometrium, PID can itself lead to more serious complications such as ectopic pregnancy, infertility, and chronic pelvic pain. More than one million women develop PID in the U.S. each year, resulting in health care costs exceeding $5.5 billion.
Chlamydia screening reduces incidence of PID
Scholes' and colleagues' research of approximately 1,800 females at Group Health in the late 1980s identified several factors that place a woman at high risk for chlamydia infection:
- single marital status
- aged 24 or less
- black race
- recent douching
- no previous pregnancies
- intercourse with two or more partners in the previous year
Most of the women identified with Chlamydia trachomatis in this study were asymptomatic. This finding led to the next step, a randomized trial to test whether screening asymptomatic women at increased risk for chlamydia infection could reduce the incidence of PID. It did—by a whopping 56 percent. "We made the link showing that more serious consequences of chlamydia infection—PID—do decline when you screen asymptomatic women for chlamydia," says Scholes. "The take-home message is that women without symptoms should be tested if there are risk factors. If you wait for symptoms, you get more PID."
The study, published in the May 1996 issue of the New England Journal of Medicine and termed "landmark" in an accompanying editorial, has had a notable impact on public health. The results prompted the Centers for Disease Control and Prevention to recommend that selective screening for cervical chlamydia infection be added to the Health Plan Employer Data and Information Set (HEDIS) outcome measures used to evaluate the performance of managed-care organizations. Also, the recently released 3rd edition of the United States Preventive Services Task Force guidelines gave chlamydia screening of high-risk women an "A" recommendation based largely on this evidence. In addition, Group Health adopted its own evidence-based chlamydia screening guideline in 1997.
According to the Group Health guideline, all sexually active females aged 12 to 20 should be screened annually; sexually active women aged 21 to 25 should be screened every other year; and older women on an "as needed" basis, especially if they have changed sexual partners in the last year. This guideline reflects the fact that adolescents and young women are at the highest risk for STDs because of a higher likelihood of having: 1) multiple sex partners; 2) unprotected intercourse; and 3) partners at a higher risk for infection.
Translating research into practice
Although Group Health gave this guideline its highest rating when it was developed in 1997, work still needs to be done to implement the guideline throughout the organization. Toward that end, Scholes and Robert S. (Tom) Thompson, MD, a CHS investigator and head of GHC's Department of Preventive Care, recently received funding to evaluate strategies designed to maximize clinicians' compliance with the guideline. The grant comes from the Agency for Healthcare Research and Quality (AHRQ), which has a program focused on "translational" research. This genre of research seeks to close the gap between what is known through research and what is actually done in clinical practice.
The main goal of this randomized trial is to increase chlamydia screening rates among sexually active women aged 14 to 20 from 40 percent to at least 50 percent. What's the main barrier to screening? For the most part, it's a matter of awareness. Providers used to perform chlamydia screening primarily during a Pap exam using cervical swabs. Now tests can be done using urine samples as well. So, it's feasible for a young woman to visit her health care provider for a cold and to easily be tested for chlamydia. "The challenge is to raise the awareness of both the patient and provider that chlamydia screening is appropriate and important during all types of contact with the health care system," says Scholes.
Tailored intervention improves condom use
While better screening and treatment can reduce the burden of STDs, other strategies include preventing infection through behavioral changes. These can include delaying the initiation of intercourse, reducing one's number of sex partners, and using barrier contraceptives such as condoms. In another recently completed study, Scholes and colleagues conducted a randomized trial to test the effectiveness of a self-help intervention for increasing condom use among women aged 18 to 24 who were at high risk for STD/HIV infection. It's an important issue because the burden of STDs is disproportionately high among young women, and in the case of HIV infection, rates among heterosexual young women have increased markedly in recent years. Despite these circumstances, young women at risk for heterosexually acquired STD/HIV have been less targeted for prevention programs.
Scholes and co-Principal Investigator Colleen McBride of Duke University carried out a trial at Group Health and Duke in which 1,210 sexually active young women were randomized to receive either Usual Care or a "tailored intervention." This intervention included a computer-generated, glossy magazine with contents partially individualized according to the participant's answers to a baseline survey. The individualized, or "tailored" messages were created based on questions about topics such as perceived STD risk, intentions to use condoms, and perceived barriers to condom use. For example, if a woman indicated on her survey that she felt uncomfortable discussing condoms with her partner, her individualized materials would include suggested language for broaching the topic. In addition to the tailored materials, intervention subjects received condoms and a condom carrying case. Three months later, they received a newsletter "booster" containing more tailored messages and condoms.
At six months, intervention subjects were almost twice as likely as controls to have used a condom in the last three months. Interestingly, the effect of the intervention was most significant among women who reported having a "primary" partner. This is important, Scholes explains, because some studies have shown that women tend to be less conscientious about condom use with "primary" partners, whom they might perceive as being safer. Indeed, in the control group, rates of condom use with primary partners declined over time while rates in the intervention group remained steady.
Women in the intervention group also reported a higher proportion of episodes of intercourse using condoms, increased confidence to use condoms, and greater likelihood of carrying condoms and of having discussions about condoms with a partner. Scholes points out that these encouraging results were achieved despite various challenges. For example, high baseline condom-use rates in the prior three months (72 percent) could have made an intervention effect more difficult to detect. Also, the women were proactively recruited and, on average, perceived themselves to be at relatively low risk of contracting HIV/STD. Therefore, motivating condom use might have been tougher among this group than among volunteers or STD clinic patients.
Scholes points out that if the intervention effect were extrapolated to the sizeable population of sexually active 18- to-24-year-old women at similar risk to those in this study, the public health impact would be considerable. As a next step, Scholes is interested in pursuing the question "How much tailoring is enough?" She would also like to evaluate some translational strategies for this research; that is, to explore ways that STD-related tailoring can be effectively implemented in community and various health care settings.
Scholes plans to continue focusing on public health in the future. "I really feel fortunate to have been involved in research that is both personally gratifying and that could also contribute to bettering women's health. I think it's particularly exciting to work in a research setting that's closely allied with the health care delivery system because it allows us to explore and evaluate ‘real world' applications of promising research," she says.