Division of Cardiology, Department of Cardiac Sciences, University of Calgary, Calgary, Canada.
Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee.
J Am Coll Cardiol. 2016 Jul 5;68(1):1-9. doi: 10.1016/j.jacc.2016.04.030.
There is limited evidence whether being on fludrocortisone prevents vasovagal syncope.
The authors sought to determine whether treatment with fludrocortisone reduces the proportion of patients with recurrent vasovagal syncope by at least 40%, representing a pre-specified minimal clinically important relative risk reduction.
The multicenter POST 2 (Prevention of Syncope Trial 2) was a randomized, placebo-controlled, double-blind trial that assessed the effects of fludrocortisone in vasovagal syncope over a 1-year treatment period. All patients had >2 syncopal spells and a Calgary Syncope Symptom Score >-3. Patients received either fludrocortisone or matching placebo at highest tolerated doses from 0.05 mg to 0.2 mg daily. The main outcome measure was the first recurrence of syncope.
The authors randomized 210 patients (71% female, median age 30 years) with a median 15 syncopal spells over a median of 9 years equally to fludrocortisone or placebo. Of these, 96 patients had ≥1 syncope recurrences, and only 14 patients were lost to follow-up before syncope recurrence. There was a marginally nonsignificant reduction in syncope in the fludrocortisone group (hazard ratio [HR]: 0.69: 95% confidence interval [CI]: 0.46 to 1.03; p = 0.069). In a multivariable model, fludrocortisone significantly reduced the likelihood of syncope (HR: 0.63; 95% CI: 0.42 to 0.94; p = 0.024). When the analysis was restricted to outcomes after 2 weeks of dose stabilization, there was a significant benefit due to fludrocortisone (HR: 0.51; 95% CI: 0.28 to 0.89; p = 0.019).
The study did not meet its primary objective of demonstrating that fludrocortisone reduced the likelihood of vasovagal syncope by the specified risk reduction of 40%. The study demonstrated a significant effect after dose stabilization, and there were significant findings in post hoc multivariable and on-treatment analyses. (A randomised clinical trial of fludrocortisone for the prevention of vasovagal syncope; ISRCTN51802652; Prevention of Syncope Trial 2 [POST 2]; NCT00118482).
目前尚缺乏氟氢可的松预防血管迷走性晕厥的有效性证据。
本研究旨在确定氟氢可的松治疗是否能将血管迷走性晕厥的复发率降低至少 40%，这是预先设定的最小临床重要相对风险降低值。
多中心 POST 2 （预防晕厥试验 2）是一项随机、安慰剂对照、双盲试验，评估了氟氢可的松治疗 1 年期间血管迷走性晕厥的效果。所有患者均有≥2 次晕厥发作和 Calgary 晕厥症状评分>-3。患者接受氟氢可的松或匹配的安慰剂治疗，最高耐受剂量为 0.05 至 0.2mg/d。主要结局指标是首次晕厥复发。
研究人员共纳入 210 名患者（71%为女性，中位年龄 30 岁），中位随访 9 年，共发生 15 次晕厥发作，随机分为氟氢可的松组和安慰剂组。其中 96 名患者发生≥1 次晕厥复发，仅 14 名患者在晕厥复发前失访。氟氢可的松组的晕厥复发率略有降低，但无统计学意义（风险比 [HR]：0.69：95%置信区间 [CI]：0.46 至 1.03；p=0.069）。多变量模型分析显示，氟氢可的松可显著降低晕厥的发生风险（HR：0.63；95%CI：0.42 至 0.94；p=0.024）。当分析仅限于剂量稳定后 2 周的结果时，氟氢可的松的治疗效果具有显著意义（HR：0.51；95%CI：0.28 至 0.89；p=0.019）。
本研究未达到其主要目标，即证明氟氢可的松可降低 40%的血管迷走性晕厥风险。研究显示在剂量稳定后有显著效果，且事后多变量分析和治疗分析也有显著结果。（氟氢可的松预防血管迷走性晕厥的随机临床试验；ISRCTN51802652；预防晕厥试验 2 [POST 2]；NCT00118482）。
