Does Sex Modify the Effect of Endovascular Treatment for Ischemic Stroke?

A Subgroup Analysis of 7 Randomized Trials

Vicky Chalos, MD; Inger R. de Ridder, MD, PhD; Hester F. Lingsma, PhD; Scott Brown, PhD; Robert J. van Oostenbrugge, MD, PhD; Mayank Goyal, MD, PhD; Bruce C.V. Campbell, PhD; Keith W. Muir, MD; Francis Guillemin, MD, PhD; Serge Bracard, MD; Philip White, MD; Antoni Davalos, MD; Tudor G. Jovin, MD; Michael D. Hill, MD; Peter J. Mitchell, MD; Andrew M. Demchuk, MD; Jeffrey L. Saver, MD; Wim H. van Zwam, MD, PhD; Diederik W.J. Dippel, MD, PhD; on behalf of the HERMES Collaborators

Disclosures

Stroke. 2019;50(9):2413-2419. 

In This Article

Abstract and Introduction

Abstract

Background and Purpose: Previous studies have reported less favorable outcome and less effect of endovascular treatment (EVT) after ischemic stroke in women than in men. Our aim was to study the influence of sex on outcome and on the effect of EVT for ischemic stroke in recent randomized trials on EVT.

Methods: We used data from 7 randomized controlled trials on EVT within the HERMES collaboration. The primary outcome was 90-day functional outcome (modified Rankin Scale). We compared baseline characteristics and outcomes between men and women. With ordinal logistic regression, we evaluated the association between EVT and 90-day functional outcome for men and women separately, adjusted for potential confounders. We tested for interaction between sex and EVT.

Results: We included 1762 patients in the analyses, of whom 833 (47%) were women. Women were older (median, 70 versus 66 years; P<0.001), were smoking less often (30% versus 44%; P<0.001), and had higher collateral grades (grade 3: 46% versus 35%; P<0.001) than men. Functional independence (modified Rankin Scale score, 0–2) at 90 days was reached by 318 women (39%) and 364 men (39%). The effect of EVT on the ordinal modified Rankin Scale was similar in women (adjusted common odds ratio [acOR], 2.13; 95% CI, 1.47–3.07) and men (acOR, 2.16; 95% CI, 1.59–2.96), with a P for interaction of 0.926.

Conclusions: Sex does not influence clinical outcome after EVT and does not modify treatment effect of EVT. Therefore, sex should not be a consideration in the selection of patients for EVT.

Introduction

Previous studies have reported less favorable outcome[1–3] and less effect of endovascular treatment (EVT)[4–8] after ischemic stroke among women compared with men. EVT was proven to be safe and effective in a meta-analysis of 5 randomized controlled trials (RCTs) within the Highly Effective Reperfusion Using Multiple Endovascular Devices (HERMES) collaboration.[7] As with the results of new and upcoming clinical trials more patients seem to benefit from EVT, individualized selection of patients for EVT has become of increased importance. This is best done by combining prognostic information from multiple clinical and radiological characteristics.[9] However, uncertainty remains about the size of the treatment effect in specific subgroups, such as in women. In MR CLEAN (A Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands), a significant interaction between sex and EVT was found.[4] Men experienced a major benefit from EVT, whereas no significant treatment effect of EVT was found in women. The meta-analysis of HERMES did not confirm these findings but did not further elaborate on this topic, and baseline characteristics by sex were not reported.[7] Since then, 2 more RCTs on EVT have been added to the HERMES collaboration data.[10,11] We aimed to provide more insight on the influence of sex on outcome and on the effect of EVT for ischemic stroke in patient-pooled data of the 7 RCTs within the HERMES collaboration.

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