1. 新光醫院 實證醫學競賽 • 分組報告組別：侯勝文 王瑞芳 陳欣伶 http://ELC.skh.org.tw/

2. Scenario • 一28歲女性已服用口服避孕藥6年 • 求診時表示看報章雜誌後發現口服避孕藥可能會增加心血管疾病而擔心不已 • 病史： • 不抽煙、不喝酒 • 家族無心血管疾病 • 她的問題：「我是否該停止使用口服避孕藥呢？」

3. PICO • P: pre-menopause woman without history of smoking and hypertension, • I: oral contraceptives • C: no use of oral contraceptives • O: cardiovascular risk

4. Database Source • 資料庫資源： • PubMed • Medline • UpToDate • Cochrane library

5. Search Terms & Strategy • 搜尋關鍵字： • oral contraceptive • cardiovascular risk • Ischemic stroke • 搜尋歷程(請描述如何縮小搜尋範圍)： • Human • adult • female • English • Clinical trial

6. 第一篇 Critically Appraised Article • 標題：Estimates of the risk of cardiovascular death attributable to low-dose oral contraceptives in the United States. • 出處：Am J Obstet Gynecol. 1999 Jan;180(1 Pt 1):241-9. • 研究設計：Inception cohort study • 研究結果分析(results)：Attributable risk of death from cardiovascular disease resulting from oral contraceptive use is 0.06 and 3.0 per 100,000 nonsmokers 15 to 34 years of age and 35 to 44 years of age, respectively • NNH = 1660,000 • 結論： • 證據強度(level of evidence)： Ib • Grade of recommendation：A

7. 第二篇 Critically Appraised Article • 標題：Combined oral contraceptives, smoking, and cardiovascular risk. • 出處：J Epidemiol Community Health. 1998 Dec;52(12):775-85 • 研究設計：Hospital-based case-control study • 研究結果分析(results)：Fatal cardiovascular events were dominated by haemorrhagic stroke and AMI, and among OC users who smoked these two diseases accounted for 80% of cardiovascular deaths among women aged 20-24 years, rising to 97% among those aged 40-44 years. Cardiovascular mortality associated with smoking was greater than that associated with OC use at all ages. Attributable risk associated with OC use was 1 death per 370,000 users annually among women aged 20-24 years, 1 per 170,000 at ages 30-34 years, and 1 per 37,000 at ages 40-44 years. Among smokers, the cardiovascular mortality attributable to OC use was estimated to be about 1 per 100,000 users annually among women aged less than 35 years, and about 1 per 10,000 users annually among those above the age of 35 years. The incidence of fatal cardiovascular events among women aged less than 35 years is low . • 結論： • 證據強度(level of evidence)：IIIb • Grade of recommendation：B

8. 第三篇 Critically Appraised Article • 標題：Ischemic stroke risk with oral contraceptives: A meta-analysis. • 出處：JAMA 2000 Jul 5;284(1):72-8 • 研究設計：meta-analysis • 研究結果分析(results)：A meta-analysis of 16 epidemiologic studies found that a nonsmoking, normotensive woman's annual stroke risk would be expected to increase from 4.4 to 8.5 per 100,000 with use of low estrogen oral contraceptives. Thus, treatment of 24,000 women would lead to one additional ischemic stroke each year. • NNH = 11764 to 22727 • 結論： • 證據強度(level of evidence)：I • Grade of recommendation：A

9. Clinical Application • 請嘗試以去學術化術語的方式回答家屬的問題 • 回答： • 使用OC的好處： • 1.避免懷孕：可減少財務、時間支出，避免周產期死亡率與罹病率 • 2.減少缺鐵性貧血的機會（月經量少） • 3.減少子宮內膜異位的機會 • 4.減少卵巢癌與子宮內膜癌（若含黃體素(progesterone)）的機會 • 5.減少停經後大腿骨折的機會 • 6.. • 使用OC的缺點： • 1.輕微增加心血管疾病，但病患僅28歲，不抽煙又無高血壓，本來的發生率就很低（這也是為什麼沒有RCT的原因），所以危險性幾乎可以忽略 2. 輕微增加腦血管疾病的風險 • 臨床應用是否會遭遇困境？ • 回答：多為國外的study,缺乏針對黃種女性/台灣女性的研究. 長時間的使用是否會有其他副作用尚待大型研究證實.

11. Your Conclusions • 請寫下你們組員相互討論的最後結論： • 若無高血壓或抽煙等心血管疾病危險因子的孕齡婦女, 使用口服避孕藥造成心血管疾病的機會非常低 • 研究亦處出使用口服避孕藥對於腦血管疾病有增加的風險. • 使用口服避孕藥有許多臨床上發現已知的好處,但使用與否仍須與病患討論.

12. Level of Evidence Grades of Recommendation

13. 參考資料：臨床建議