Forget the routine pelvic exam. When the goal is to prevent the serious complications of sexually transmitted diseases (STDs) in adolescent girls, a simple urine test will reach more teens and at a lower cost.
That is the conclusion drawn by adolescent health specialist Mary-Ann Shafer, MD, and her UC San Francisco colleagues in an article published in the February 14, 1999 issue of the Archives of Pediatric Adolescent Medicine. "New technology allows laboratories to very accurately detect signs of chlamydia and gonorrhea in urine samples, Shafer said. This urine test is nearly as effective as the traditional STD tests for gonorrhea and chlamydia using samples taken from the woman's cervix."
"We know from earlier research that as many as one-third of adolescent girls and women avoid screening for STDs because they fear the embarrassment and pain of a pelvic exam, which is required for the traditional tests," Shafer said. "So in the real world, urine tests will detect more cases of asymptomatic STDs."
The UCSF researchers calculated that an annual urine test to screen for STDs among the estimated five million sexually active 15 to 19 year old young women in the U.S would save $202.5 million each year in comparison to universal annual pelvic exams, the method currently recommended by public health experts.
TESTS FOR REAL-WORLD TEENS
"Probably the most important application of urine tests is their use on young women and men who have chlamydia or gonorrhea, but have no symptoms at all," Shafer said. To detect infection, urine based testing does not require the invasive and often uncomfortable pelvic exam for girls or a swab test which can be painful for boys. That means teens can be screened outside of traditional clinic settings -- in school based clinics, recreational centers, and other settings where teens congregate.
When STDs are detected in the early stages, before symptoms begin, patients can be treated with antibiotics to reduce the chances that the disease will spread and prevent serious complications like Pelvic Inflammatory Disease (PID). The long term effects of PID, including infertility and ectopic or tubal pregnancies, can be painful, costly and life-threatening.
Shafer is professor of pediatrics and associate director of the adolescent medicine at UCSF. Her co-authors are Robert H. Pantell, MD, professor and chief of the division of general pediatrics, and Julius Schachter, PhD, professor of laboratory medicine. Shafer and Pantell care for children and adolescents as members of Lucile Packard Children's Health Services at UCSF. Schachter has been a leader in identifying the effects of chlamydia and other sexually transmitted diseases. He and Shafer first proposed using urine tests to screen adolescents for STDs in a letter to the New England Journal of Medicine in November, 1996, because urine test accuracy had been dramatically improved by new methods called amplified nucleic acid tests.
For their current study, Shafer and Schachter teamed up with Pantell to mathematically model the costs and benefits of urine test screening based on amplified nucleic acid tests such as the ligase chain reaction or LCR. In their mathematical model, the researchers calculated that if 90 percent of a population of 100,000 sexually active adolescent women received urine-based screening tests, the tests would detect 1,620 cases of gonorrhea and 4,860 cases of chlamydia.
Treatment of STDs detected in this cohort would help prevent 1,093 cases of PID. If pelvic exams were used as the sole screening method, only about 70 percent of adolescent women could be expected to agree to an exam, and an estimated 898 cases of PID would be prevented. The researchers calculated that the cost to protect each young woman from serious disease would be twice as much with a pelvic exam as with a urine test.
"Sexually transmitted diseases continue to be epidemic among adolescents, especially females," Shafer noted. "Teenagers account for one-quarter of the 12 million STD cases occurring annually in the U.S., and the rate of gonorrhea among 15 to 19 year old women is six times that of the nation as a whole."
Current recommendations from the United States Public Health Service and professional medical societies call for routine screening for chlamydia and gonorrhea in all sexually active females under age 20, since these diseases often are asymptomatic. In some higher risk populations of teens it has been suggested that such screening take place every six months. "Urine tests would make this much more feasible, by expanding the number of young women who get routine tests," Shafer said.
"Also, resources can be directed to screening boys as well as girls," she said. "And doctors will have more time to spend on counseling, reminding their young patients to try to abstain from sex, to use condoms consistently if they have sex, and not to have sex with people they don't know."
Testing and treatment of early cases of STDs is recommended as part of a strategy that also includes primary prevention - assisting youth to delay the onset of sexual activity, and encouraging sexually active adolescents to use condoms and limit the numbers of their sexual partners.
However, prevention efforts, including screening, still do not reach many young people. Recent studies have shown that only half of at-risk teens are screened for STDs during routine health exams, and almost 40 percent of pediatricians never perform pelvic exams upon their sexually active adolescent patients who need them.
Pelvic exams are used to detect other diseases that a urine test could not pick up, including cervical cancer. However, this cancer is so rare among young women that it would take one-half million pelvic exams with Pap smears to detect one case, the researchers noted. They suggested pelvic exams for young women who may be at risk for cervical cancer. But for the general population, they suggested delaying routine Pap smears until age 18 or three years after a woman begins sexual activity.
The UCSF research was supported by federal grants to Shafer from the Interdisciplinary Adolescent Health Training Health Project, Bureau of Maternal and Child Health. Pantell's participation was supported in part by the Policy Information and Analysis Center for Middle Childhood-Adolescent Grant, Bureau of Maternal and Child Health. Schachter is supported by grants from the National Institute of Allergy and Infectious Diseases to evaluate and help in the development of diagnostic tests for sexually transmitted diseases.
Journal
Archives of Pediatrics and Adolescent Medicine