Sheringham小姐表示，若未改善對披衣菌盛行率、以及感染時相關併發症之風險程度的瞭解，其他披衣菌篩檢的研究也將和「Prevention of Pelvic Infection trial」試驗一樣，面臨研究設計與詮釋上的挑戰。
倫敦BUPA基金會、加州聖地牙哥Gen-Probe公司支持本研究，研究作者們宣告沒有相關財務關係。
BMJ. 線上發表於2010年4月8日。
Screening for Chlamydia Once a Year May Not Prevent Pelvic Inflammatory Disease
By Nancy Fowler Larson
Medscape Medical News
April 9, 2010 — Annual screenings for chlamydia may not be sufficient to avert pelvic inflammatory disease (PID) in women, according to an article published in the published online April 8, 2010, in the British Medical Journal.
PID that can result from untreated chlamydia can scar the fallopian tubes, leading to tubal infertility and ectopic pregnancy. With more than 3 million new infections every year, chlamydia is the most frequently occurring bacterial sexually transmitted disease (STD) in the United States and Europe. However, most chlamydial infections remain asymptomatic and undiagnosed. In the United States, screening is recommended for sexually active women 25 years old and younger, and in England, for those younger than 25 years.
"In many developed countries, screening programmes for chlamydia have been set up to reduce transmission and reproductive tract morbidity," write Pippa Oakeshott, MD, from the Division of Community Health Sciences, St. George's, University of London, United Kingdom, and colleagues. "A more accurate estimate of the rate of progression of genital chlamydial infection to pelvic inflammatory disease is also urgently needed to evaluate the cost effectiveness of screening programmes."
The September 2004 through October 2006 randomized controlled Prevention of Pelvic Infection trial involved 2529 sexually active, nonpregnant women students with an average age of 21 years. Participants self-reported details about their sexual health. They provided vaginal swabs at the study's onset, which were either tested immediately (screening group) or after 1 year (deferred screening control). Those in the screening group whose samples showed infection were urged to get treatment.
One year later, follow-up vaginal swabs were taken, and participants completed another questionnaire regarding their sexual behavior and any PID symptoms, which include pelvic pain, unusual bleeding, and discharge.
PID Occurred More Often in Women With Initial Negative Tests for Chlamydia
The results showed that at baseline, 5.4% (n = 68) of the screening group and 5.9% (n = 75) of the control group were infected with chlamydia. A 1-year follow-up of 94% of the participants resulted in the following findings:
1.3% (15/1191) of the screening group had PID compared with 1.9% (23/1186) of the control group (relative risk, 0.65; 95% confidence interval [CI], 0.34 - 1.22)
1.6% (1/63) of the screening group who had chlamydia at the study's onset developed PID during a 1-year period (relative risk, 0.17; 95% CI, 0.03 - 1.01) compared with 9.5% (7/74) of the control group (95% CI, 4.7% - 18.3%)
PID was found most often in those who tested negative for chlamydia at the study's onset (79%; 30/38)
Investigators concluded that the majority of PID cases over 12 months were not prevented by a single chlamydia screen, and that both the effectiveness and the cost-effectiveness of this policy may have been previously overestimated.
"Our findings suggest that to prevent one case of clinical pelvic inflammatory disease over 12 months, it may be necessary to screen 147 women for chlamydial infection or to treat 13 women who are positive for chlamydia," the authors write. "If the incidence of pelvic inflammatory disease in women with chlamydial infection has been overestimated, and particularly if it is less than 10%, then the cost effectiveness of screening might be exaggerated."
The authors recommended more-frequent testing for high-risk candidates such as women with a history of chlamydia or those who have a new sexual partner.
Several limitations to the study were noted.
The trial was underpowered to discover any effect of screening that was statistically significant and may not be generalizable to other populations such as women from different ethnic groups, higher risk women such as sex workers, or non-UK populations.
1 in 5 subjects who acted on recommendations to be screened independently had a greater incidence of chlamydia, which may have minimized the effect of the intervention.
A lack of sensitivity and specificity of PID diagnosis, absence of detailed medical records in some cases, and the inherent possibility of error in self-reporting may have affected the results as well.
According to Jessica Sheringham, medical research council fellow, from the Department of Epidemiology and Public Health, University College London, "it is disappointing but not surprising" that the study was unable to conclude with certainty the effect of screening on the prevalence of PID.
"The risk of [PID] in women who were screened immediately was lower than in control participants (relative risk 0.57, 95% confidence interval 0.29 to 1.11) after adjustment for symptoms at baseline, but this reduction was not statistically significant," Ms. Sheringham said in an editorial published with the research.
Ms. Sheringham said the study did provide insight into the likelihood of chlamydia leading to PID. She also noted that it highlights difficulties in obtaining evidence necessary to update public policy regarding chlamydia.
"Without an improved understanding of the prevalence of chlamydia and the extent of the risk of complications associated with infection, other trials of chlamydia screening will face challenges of design and interpretation similar to those encountered in the [Prevention of Pelvic Infection] trial," Ms. Sheringham said.
The BUPA Foundation of London and Gen-Probe of San Diego, California, supported this study. The study authors have disclosed no relevant financial relationships.
