Heparinversusenoxaparin for prevention of venousthromboembolism after trauma: Arandomized noninferioritytrial (注意红色字体)
BACKGROUND:Research comparing enoxaparin with unfractionated heparin (UFH) given every 12 hours for venous thromboembolism (VTE)prophylaxis after trauma overlooks original recommendations that UFH be given every 8 hours. We conducted a prospective,randomized, noninferiority trial comparing UFH every 8 hours and standard enoxaparin every 12 hours.We hypothesizedthat the incidence of VTE in trauma patients receiving UFH every 8 hours would be no more than 10% higher than that in patients receiving enoxaparin every 12 hours.(表达目的)
METHODS:Trauma patients who met criteria for VTE prophylaxis at a Level I trauma center were randomly assigned to 5,000-U UFHevery 8 hours or 30-mg enoxaparin every 12 hours between November 2012 and September 2014. Surveillance duplex ul-trasound was performed twice weekly on intensive care unit patients and weekly on ward patients. Primary end points were deep vein thrombosis diagnosed by duplex ultrasound and pulmonary embolism diagnosed by computed tomography angiography.(where,who,what)
RESULTS:Of 495 randomized patients, 220 received UFH and 216 received enoxaparin for analysis. Overall, 105 in the UFH group and103 in the enoxaparin group underwent VTE surveillance or diagnostic testing. In the analysis of randomized patients who received treatment, UFH was noninferior compared with enoxaparin (absolute VTE risk difference, 3.1%; 95% conﬁdence interval, j1.6% to 7.7%; p = 0.196); however, in the screening ultrasound group, the noninferiority of UFH was inconclusive(absolute VTE risk difference, 6.5%; 95% conﬁdence interval, j2.9% to 15.8%; p = 0.179). The two treatments did not differ with regard to adverse events. The pharmaceutical cost for the regimen of UFH ($2,809) was nearly 20-fold lower than that for enoxaparin ($54,138).(体现主要结果，不可只写p值)
CONCLUSION:A regimen of UFH every 8 hours may be noninferior to enoxaparin every 12 hours for the prevention of VTE following trauma.Given UFH’s cost advantage, the use of UFH for VTE prophylaxis may offer greater value. (J Trauma Acute Care Surg.2015;79: 961Y969. Copyright * 2015 Wolters Kluwer Health, Inc. All rights reserved.)(一定是结果的总结)
正如上例，在Introducation中首先讲述了VTE在创伤患者中的流行病，然后讲了现在预防的主流方法，最后提出目前方案的局限性映衬出自己研究的目的。作者是这样提出问题的：We hypothesized that the incidence of VTE in trauma patients receiving UFH every 8 hours would be no more than 10% higher (i.e., noninferior) than that in patients receiving enoxaparin every 12 hours.
P：Patients 18 years and older and at risk forVTE based on the American College of Chest Physicians guidelines were included. 14 Those with an estimated Injury Severity Score (ISS) equal to or less than 9, those expected to have a hospital length of stay less than 7 days by reason of discharge or death, and prisoners were excluded. Additional exclusion criteria included international normalized ratio of 1.2 or greater, body mass index (BMI) greater than 40, creatinine of 1.3 or greater, transfer time to our facility greater than 24 hours, and pregnancy.
I：Eligible patients was randomized to receive either 5,000 U of UFH every 8 hours
C：or30 mg of enoxaparin every 12 hours.
O：Primary end pointswere a new DVT or progression of a known below-knee DVT diagnosed by venous duplex ultra- sound (U/S) and a PE diagnosed by computed tomography angiography.Secondary end pointsincluded bleeding events and the occurrence of heparin-induced thrombocytopenia (HIT).(对于如何判断这些主次要结果都进行了详细描述，可重复性非常好)
S：A prospective, randomized, two-arm, noninferiority trial(研究类型)
样本量：任何统计推断都是在一定的样本量基础上进行的。现在大部分杂志对于RCT研究都要求写明如何计算样本量的。本文作者写道：To achieve 90% power using an a priori margin of 10% with a one-sided > of 0.025, a total of 182 patients (91 in each arm) was required。
We sought to determine whether a regimen of UFH every8 hours was inferior to standard enoxaparin every 12 hours forVTE prophylaxis in trauma patients, as similar effectivenesswould provide a cost-savings rationale favoring the use ofUFH. In the analysis of the randomized treated sample, wefound UFH every 8 hours was noninferior to enoxaparin basedon an a priori 10% noninferiority margin with an absolutedifference in VTE rates of 3% between treatment groups. Although the two treatments did not differ with regard to adverseevents, the pharmaceutical cost of the UFH regimen was nearly。。。。。对结果进行描述
Other studies in diverse patient groups reveal that UFHdelivered every 8 hours is an effective VTE prophylaxis. In1974, evaluating two different regimens of UFH (5,000 U) ingeneral surgery patients, Corrigan et al. 9 found the regimen ofevery 8 hours superior to dosing every 12 hours for the pre-vention of total DVTs as well as above-knee DVTs.。。。。。。In contrast, results of a recent prospective economicevaluationby Fowleretal。。。。。。(和之前文献进行比较)
Thus, the most cost-effective VTEchemoprophylaxis in the future may focus on nonheparinoidagents that are more effective in trauma patients. (指出未来研究方向)
Our study has several limitations. (局限性)
A regimen of UFH every 8 hours may be noninferior to enoxaparin every 12 hours for the prevention of VTE following trauma.Given UFH’s cost advantage, the use of UFH for VTE prophylaxis may offer greater value.