Oioe

作者：Nancy Fowler Larson  
出處：WebMD醫學新聞

　　April 9, 2010 — 根據線上發表於2010年4月8日英國醫學期刊(British Medical Journal)的一篇文獻，每年做一次披衣菌感染篩檢不足以預防女性的骨盆發炎疾病(pelvic inflammatory disease，PID)。
　　
　　未加治療之披衣菌感染所導致的PID會使輸卵管結疤，造成輸卵管不孕症與子宮外孕，每年有超過300萬件新感染，披衣菌感染是美國和歐洲最常發生的細菌性性傳染疾病(sexually transmitted disease，STD)，不過，多數披衣菌感染沒有症狀且未被診斷。在美國，建議有性經驗的25歲以下女性進行篩檢，在英國，則是25歲以下婦女皆篩檢。
　　
　　英國倫敦大學聖喬治社區健康科學小組Pippa Oakeshott醫師等人寫道，在許多已開發國家中，披衣菌篩檢計畫的目的在減少傳染以及生殖器發病率，亟需更準確地預估生殖器披衣菌感染導致骨盆發炎疾病之比率的方法，以評估篩檢計畫的成本效益。
　　
　　2004年9月至2006年10月間進行的「Prevention of Pelvic Infection trial」隨機控制試驗，包括了2,529名有性經驗、未懷孕的女性學生，平均年紀21歲。這些研究對象自我報告有關她們性健康方面的資料，研究開始時進行陰道拭子取樣，分成「立即檢測(篩檢組) 」或「一年後檢測(延緩篩檢控制組) 」，篩檢組的樣本若顯示感染則促使其接受治療。
　　
　　一年後，進行陰道拭子追蹤樣本採樣，研究對象完成另一份問卷，問卷內容是關於她們的性行為與任何的PID症狀，包括骨盆疼痛、不尋常出血以及分泌物。
　　
　　【最初之披衣菌檢查陰性的婦女比較常發生PID】
　　結果顯示，在開始時，篩檢組有5.4% (n = 68人)、控制組有5.9% (n = 75人)感染披衣菌，有94%的研究對象完成一年的追蹤，結果如下：
　　* 篩檢組1.3% (15/1191)有PID，控制組則是1.9% (23/1186)(相對風險為0.65；95% 信心區間[CI]為 0.34 - 1.22)。
　　* 篩檢組在研究開始時有披衣菌者，1.6% (1/63)在一年追蹤期間發生PID(相對風險為0.17；95% CI，0.03 - 1.01)，控制組有9.5% (7/74) (95% CI，4.7% - 18.3%)
　　* 研究開始時的披衣菌檢查陰性婦女比較常發生PID (79%；30/38)。
　　
　　研究者結論表示，僅僅藉由一次的披衣菌篩檢，無法預防這12個月內的多數PID案例，此項政策的效果與成本效益被高估了。
　　
　　作者們寫道，我們的發現認為，為了在12個月期間預防1例臨床骨盆發炎疾病案例，必須篩檢147名婦女的披衣菌感染、或者治療13名披衣菌陽性婦女，如果披衣菌感染婦女的骨盆發炎疾病發生率被高估了，特別是如果它不到10%，那麼，篩檢的成本效益就是言過其實。
　　
　　作者們建議，有披衣菌病史、有新的性伴侶等高風險婦女，篩檢頻率應增加。
　　
　　研究限制如下：
　　* 該試驗不足以發現篩檢的任何效果有統計上的顯著差異，無法一般化到其他族群，如其他種族、風險較高的婦女(如性工作者)、或非英國人口等。
　　* 只有五分之一的研究對象依據建議獨立篩檢，造成較高的披衣菌發生率，這可能使介入的效果減少。
　　* 缺乏PID診斷的敏感度與專一度資料、沒有這些案例的詳細病歷，自我報告的誤差可能也會影響研究結果。
　　
　　根據倫敦大學院流行病學與公共衛生系、醫學研究委員會研究員Jessica Sheringham表示，該研究無法得到篩檢對於預防PID有一定程度效果的研究結果令人失望，但不令人驚訝。
　　
　　Sheringham小姐在該研究之編輯評論中表示，校正開始時的症狀之後，立即篩檢組婦女的PID風險低於控制組研究對象(相對風險為0.57，95%信心區間為0.29-1.11)，但是未達統計上的顯著差異。
　　
　　Sheringham小姐表示，該研究提出了披衣菌可能導致PID的見解，她也指出，該研究也強調了獲得必要的證據來更新披衣菌公共衛生政策的困難。
　　
　　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.

BMJ. Published online April 8, 2010.