This Article Full Text Full Text (PDF) All Versions of this Article: 37/9/2198    most recent 01.STR.0000237086.85164.92v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sandercock, P. Articles by Lewis, S. Search for Related Content PubMed PubMed Citation Articles by Sandercock, P. Articles by Lewis, S. Related Collections Thrombolysis Related Article

(Stroke. 2006;37:2198.)
© 2006 American Heart Association, Inc.

Editorials

Sex-Based Differences in the Effect of Intra-Arterial Treatment of Stroke

A Plea to Stop Torturing the Old Data and Do Large Trials!

Peter Sandercock, MA, DM Steff Lewis, PhD

From the University of Edinburgh, Department of Clinical Neurosciences, Western General Hospital, Edinburgh, UK.

Correspondence to Peter Sandercock, University of Edinburgh, Department of Clinical Neurosciences, Western General Hospital, Edinburgh, EH4 2XU, UK. E-mail peter.sandercock@ed.ac.uk

Key Words: stroke

An extract of the first 250 words of the full text is provided, because this article has no abstract.

See related article, pages 2322–2325

This analysis sought to explore whether gender influences response to intra-arterial thrombolysis. This was stimulated by an earlier meta-analysis of the trials of intravenous recombinant tissue plasminogen activator which showed, after adjustment for baseline factors, that there was some evidence female gender modified the response to thrombolysis.¹ We feel these analyses were both inappropriate and potentially misleading.

This study does not confirm the results of the earlier meta-analysis.¹ In this study, a different treatment effect estimate has been used (using a cut-off of Rankin 1, rather than Rankin 2), and results are presented adjusted for baseline factors where the previous study presented unadjusted results. Presumably, if identical methods to the earlier meta-analysis had been used, it would not have been possible to confirm the results.

The hazards of inappropriate subgroup analyses in small trials and small meta-analyses have been highlighted by Schulz² and by Collins³; a surprising amount of statistical power is needed for the reliable detection of subgroup interaction with the effects of particular treatments. An example of the hazards of underpowered subgroup analyses is the Canadian Aspirin Trial, which was—mistakenly—interpreted as showing that aspirin was not of net benefit to women with transient ischemic attacks,⁴ and led to the FDA delaying the licensing of aspirin for stroke prevention in women. Untold numbers of women were therefore denied effective treatment with aspirin and experienced strokes that might have been avoided. It required a meta-analysis of all the available randomized trials (including data . . . [Full Text of this Article]

Related Article:

Sex-Based Differences in the Effect of Intra-Arterial Treatment of Stroke: Analysis of the PROACT-2 Study

Michael D. Hill, David M. Kent, Judith Hinchey, Howard Rowley, Alastair M. Buchan, Lawrence R. Wechsler, Randall T. Higashida, Nancy J. Fischbein, William P. Dillon, Michael Gent, Carolyn M. Firszt, Gregory A. Schulz, Anthony J. Furlan on behalf of the PROACT-2 Investigators
Stroke 2006 37: 2322-2325. [Abstract] [Full Text] [PDF]

This article has been cited by other articles:

				Thrombolysis: For Female Stroke Victims, It's About Time Journal Watch Women's Health, October 5, 2006; 2006(1005): 4 - 4. [Full Text]