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


Stroke. 2019;50(9):2413-2419. 

In This Article


After excluding 2 patients with unknown sex, we included 1762 patients in the analyses, of whom 929 (53%) were men and 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 grade (grade 3: 46% versus 35%; P<0.001) than men (Table 1). There were no differences in medical history, especially atrial fibrillation, prestroke mRS, administration of tPA, and onset to randomization or groin puncture times between women and men.

The median 90-day mRS was the same for women and men in the intervention groups, and for women and men in the control groups, with significant differences between the intervention groups versus the control groups (4.0 versus 3.0; P<0.001; Table 2). Functional independence (mRS, 0–2) at 90 days was reached by 318 women (39%) and 364 men (39%), with a similar distribution among the intervention and control groups, significantly in favor of the intervention group (Figure 1; Table 2). Mortality at 90 days was 15% for women and 16% for men. Mortality also did not differ between the intervention and control group for both sexes. There was no difference between women and men in symptomatic intracranial hemorrhage (3.7% versus 3.6%) or in successful reperfusion (75% versus 76%). FIV was smaller in women (32 mL) than in men (53 mL; Table 2). FIV was also significantly smaller in the intervention group than in the control group in both women (27 versus 40 mL; P=0.009) and men (39 versus 70 mL; P<0.001; Table 2), with an adjusted beta of −0.26 (95% CI, −0.49 to −0.02) and −0.33 (95% CI, −0.50 to −0.15; Table I in the online-only Data Supplement), respectively.

Figure 1.

Distribution of the modified Rankin Scale (mRS) score in percentages among the intervention and control group, for all patients and by sex. mRS was missing in 5 patients of the intervention group (4 women and 1 man) and in 15 patients of the control group (9 women and 6 men).

Treatment effect of EVT on the ordinal mRS was comparable in women (adjusted common odds ratio, 2.13; 95% CI, 1.47–3.07) and men (adjusted common odds ratio, 2.16; 95% CI, 1.59–2.96) with a P for interaction of 0.926 (Figure 2). Similarly, there was no difference between women and men in the effect of any of the additional secondary outcomes (Figure 2; Table I in the online-only Data Supplement).

Figure 2.

Forest plot showing adjusted treatment effect (adjusted [common] odds ratios [a(c)ORs] and 95% CI) of endovascular treatment (EVT) per outcome measure for women and men. Adjusted for age, baseline NIHSS, time from onset to randomization, diabetes mellitus, prior stroke, occlusion location, intravenous tPA administration, collateral grade, and trial (as random effect). mRS indicates modified Rankin Scale; and sICH, symptomatic intracranial hemorrhage.