This article is more than 5 years old. Information may no longer be current.
Outcomes after stroke not influenced by sex after adjustment for confounders
Click Here to Manage Email Alerts
For patients with stroke, functional outcome without thrombolization was similar between sexes, and reaction to IV recombinant tissue-type plasminogen activator was similar when adjusting for prognostic factors, according to new data.
“Some important risk factors in stroke are more prevalent in females than males — for example, [diabetes], atrial fibrillation and arterial hypertension,” Christian Hametner, MD, MSc, of the University of Heidelberg in Germany, and colleagues wrote. “All of these are known to influence the pathophysiology and functional outcome of stroke.”
Hametner and colleagues used data from the Virtual International Stroke Trials Archive. The researchers matched men to women (n = 4,575; 48% women) and assessed outcome through the 7-point modified Rankin scale (mRS) at 90 days after ischemic stroke.
Potential confounders that were assessed included age, NIH Stroke Scale (NIHSS) score, onset of stroke to time of randomization, BMI, stroke localization and risk factors including hypertension, diabetes, smoking, AF and MI.
Comparable outcomes
In patients who did not receive IV thrombolysis (n = 3,504), mRS was similar in women vs. men (OR = 0.93; 95% CI, 0.83-1.06) when adjusting for stroke- and sex-related prognostic factors. Favorable outcomes (OR = 1.03; 95% CI, 0.88-1.22) and good outcomes (OR = 0.93; 95% CI, 0.79-1.09) were also comparable between the sexes, according to the researchers.
An initial analysis suggested a difference in favor of men in response to recombinant tissue-type plasminogen activator (r-tPA; OR = 0.895; 95% CI, 0.813-0.986). However, after matching and adjusting for potential confounders, no significant effect between sexes was associated with r-tPA (P for interaction = 0.46; relative excess risk because of interaction = 0).
The number needed to treat was similar between men and women to achieve an mRS score of 0 or 1 (men, 11.1; women, 11.2) and an mRS score of 0 to 2 (men, 6.7; women, 6.8) at 90 days after stroke, according to the researchers.
Mortality was significantly lower in women than in men (HR = 0.82; 95% CI, 0.74-0.95). Adjustments for r-tPA, age and baseline NIHSS score did not significantly change the results (HR = 0.81; 95% CI, 0.7-0.94).
“As for the sex-specific response to r-tPA, we could not reject the null hypothesis of a common treatment effect of r-tPA between the sexes,” researchers wrote. “We could not find evidence for a meaningful relationship between sex, r-tPA and bleeding complications. Finally, we found that consideration of a nonlinear sex-by-age interaction significantly improved estimates of outcomes — this may be important to be considered in future analyses of sex of data on stroke patients.”
Idealized scenario
In an accompanying editorial, Valeria Caso, MD, PhD, and Maurizio Paciaroni, MD, of the stroke unit at the Santa Maria della Misericordia Hospital, University of Perugia, Italy, called the study “elegant and sophisticated.” However, they wrote: “The results cannot be interpreted as if they reflected the real picture throughout the world. That is, the outcomes were undoubtedly influenced by the fact that all patients received the best treatment available, and moreover, these were not limited by social conditions that could have hindered the delivery of such treatment. Where these disparities have been addressed with effective programs, improvements in once worse outcomes for women have been turned around.” – by Cassie Homer
Disclosure: Hametner, Caso and Paciaroni report no relevant financial disclosures. Two researchers report financial ties with Boehringer Ingelheim.
Perspective
Back to TopRichard M. Zweifler, MD
There are relatively few well-designed studies investigating gender differences in the natural history of ischemic stroke or gender differences in the treatment effect of tPA. This well-designed study suggests no gender difference in ischemic stroke outcome regardless of whether tPA was administered. This study, however, is not likely to impact clinical practice. Future research in this area should replicate these data in a population-based sample prior to generalizability.
Click Here to Manage Email Alerts