Koster T, Small R A, Rosendaal F R, Helmerhorst F M
Department of Clinical Epidemiology, University Hospital Leiden, The Netherlands.
J Intern Med. 1995 Jul;238(1):31-7. doi: 10.1111/j.1365-2796.1995.tb00896.x.
The majority of post-thrombotic women are barred from using oral contraceptives. We evaluated this policy for its clinical relevance.
A meta-analysis of controlled studies between 1960 and 1993.
A Medline computer search, from 1966 to 1993, in multiple languages, with the following index terms: thrombosis, thrombopheblitis, vein, venous, pulmonary embolism, contraceptives, oestrogen, oral.
A total of 588 articles or abstracts were reviewed for controlled studies, in which an index group was compared with a control group. Included were one randomized trial, six follow-up studies and eight case-control studies.
Summary thrombosis risk for oral contraceptive users, number needed to discontinue oral contraceptives to prevent one (recurrent) thrombosis, comparison of additional unwanted pregnancies and postpartum thrombosis between alternative birth-control methods.
The studies proved highly heterogeneous with regard to size and direction of the risk estimate. The summary relative risk of first thrombosis during oral contraceptive use was 2.9 (95% CI, 0.5-17). Since the risk of thrombosis recurrence is not well known, we estimated alternatives, making various hypothetical assumptions, wherein women would continue to take oral contraceptives after a first episode of thrombosis, or stop and switch to use of an intra-uterine device, condom or the progestogen-only pill. Depending on the assumptions with regard to recurrence risk and the existence of possible subgroups with genetic coagulation defects, the cost-benefit ratio of advising against the use of oral contraceptives after a first thrombosis varied tremendously.
Our analysis shows that we lack the necessary data for recurrence risk of venous thrombosis during continuing use of oral contraceptives, or after switching to other modes of contraception. This reflects the clinical uncertainties that result in highly contradictory advice to young women who have experienced a first thrombosis. Only follow-up studies on recurrence risk will settle the issue.
大多数血栓形成后的女性被禁止使用口服避孕药。我们评估了这一政策的临床相关性。
对1960年至1993年间的对照研究进行荟萃分析。
1966年至1993年通过多语言对Medline进行计算机检索，检索词如下：血栓形成、血栓性静脉炎、静脉、静脉的、肺栓塞、避孕药、雌激素、口服。
共审查了588篇文章或摘要以寻找对照研究，其中将一个指标组与一个对照组进行了比较。包括一项随机试验、六项随访研究和八项病例对照研究。
口服避孕药使用者的血栓形成总体风险、为预防一次（复发性）血栓形成而需要停用口服避孕药的人数、不同避孕方法之间意外妊娠和产后血栓形成情况的比较。
这些研究在风险估计的大小和方向方面存在高度异质性。口服避孕药期间首次发生血栓形成的汇总相对风险为2.9（95%可信区间，0.5 - 17）。由于血栓形成复发的风险尚不清楚，我们进行了各种假设估计替代方案，即女性在首次血栓形成发作后继续服用口服避孕药，或停药并改用宫内节育器、避孕套或仅含孕激素的避孕药。根据关于复发风险的假设以及可能存在的遗传性凝血缺陷亚组，在首次血栓形成后建议停用口服避孕药的成本效益比差异极大。
我们的分析表明，我们缺乏关于继续使用口服避孕药期间或改用其他避孕方式后静脉血栓形成复发风险的必要数据。这反映了临床的不确定性，导致对经历过首次血栓形成的年轻女性的建议高度矛盾。只有关于复发风险的随访研究才能解决这个问题。
