A meta-analysis to determine the effect of preinjury antiplatelet agents on mortality in patients with blunt head trauma

Abstract

Introduction. Anticoagulation abnormalities have been recognized for several decades as potential risk factors for increasing the risk of traumatic intracranial haemorrhage in patients with blunt head trauma. The potential increased risk of death as a consequence has not been fully evaluated. The aim of the study was to perform a meta-analysis in order to evaluate based upon the current level of evidence whether the use of pre-injury aspirin or clopidogrel increases the risk of mortality in patients with blunt head trauma. Methods. The databases Medline and EMBASE were searched via the Ovid interface. The Medline database was also searched using the PubMed interface. Case control studies or nested case control studies were identified comparing mortality rates on patients with blunt head trauma in patients on aspirin or clopidogrel against patients not on antiplatelet agents. Results. Five studies in total were identified as suitable for the meta-analysis. Four of these studies were suitable for the aspirin meta-analysis and four for the clopidogrel meta-analysis. The common odds ratio for the aspirin meta-analysis using the Random Effects model was found to be 2.435 (95% CI: 0.637–9.314). Significant heterogeneity was present I² = 79.521. The common odds ratio for the clopidogrel meta-analysis using the Random Effects model was found to be 1.554 (95% CI: 0.320–7.536). Significant heterogeneity was present I² = 69.090. Conclusions. In summary, this meta-analysis showed a slight increased risk of death in patients with blunt head trauma who were taking pre-injury antiplatelet agents although the results did not reach statistical significance. In view of the small number of low level studies from which this meta-analysis is based, further work is required in this area.

Keywords::

• antiplatelet agents
• head injury

Declaration of interests:

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.

Appendix 1

Database: Ovid MEDLINE(R) < 1950 to October Week 1 2010 >

Search Strategy:

1 head injur$.mp. [mp = title, original title, abstract, name of substance word, subject heading word, unique identifier] (17948)

2 crani$ trauma.mp. [mp = title, original title, abstract, name of substance word, subject heading word, unique identifier] (18747)

3 crani$ injur$.mp. [mp = title, original title, abstract, name of substance word, subject heading word, unique identifier] (2299)

4 traumatic brain injur$.mp. [mp = title, original title, abstract, name of substance word, subject heading word, unique identifier] (11179)

5 or/1–4 (40395)

6 warfarin.mp. or exp Warfarin/(15884)

7 coumarin.mp. or exp Coumarins/ (36121)

8 anticoagulant.mp. or exp Anticoagulants/ (170529)

9 acetylsalicylic acid.mp. (6679)

10 exp Aspirin/ or aspirin.mp. (45393)

11 clopidogrel.mp. (5126)

12 plavix.mp. (135)

13 dipyridamole.mp. or exp Dipyridamole/ (9304)

14 persantin.mp. (221)

15 asasantin.mp. (9)

16 exp Heparin/ or heparin.mp. (75000)

17 dalteparin.mp. or exp Dalteparin/ (889)

18 enoxaparin.mp. or exp Enoxaparin/ (2725)

19 tinzaparin.mp. (268)

20 bemiparin.mp. (50)

21 zibor.mp. (1)

22 fragmin.mp. (334)

23 clexane.mp. (83)

24 innohep.mp. (16)

25 or/6–24 (251236)

26 5 and 25 (364)