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Different Strokes for Different Folks: Assessing Risk in Women

You may have noticed that men and women are different. I hope you have noticed. As the French say, vive la différence! It’s not just that one has dangly bits and the other has bumpy chests. Or that one has to shave a beard and doesn’t like to ask for directions while the other has menstrual periods and likes to discuss feelings. There are differences in physiology and in the incidence of various diseases. For instance, normal lab values for hemoglobin are higher for men than for women, and autism is more prevalent in males while multiple sclerosis is more prevalent in females.

In the past, women have been underrepresented in clinical studies; when the first studies of aspirin for cardiovascular prevention came out, we knew it was effective for men, but we didn’t have enough evidence to recommend it for women. This is changing; researchers today are more aware of the need to include women in their studies. Now the American Heart Association/American Stroke Association (AHA/ASA) has issued the first evidence-based guidelines for reducing the risk of stroke in women.

Previous guidelines were for all adults, without specifying any differences by sex. Interestingly, those guidelines said stroke was more prevalent in men than in women, directly contradicting what the new guidelines for women say. They say the lifetime risk of stroke in women is higher than in men (20% vs. 17%). In 2009, 60% of stroke-related deaths were in women. Women are different: genetic differences in immunity, coagulation, hormonal factors, reproductive factors, and social factors can influence the risk of stroke and impact stroke outcomes. The new guidelines were needed to reflect risk factors that are unique to women.

They identify 6 sex-specific risk factors:

  • pregnancy
  • pre-eclampsia
  • gestational diabetes
  • oral contraceptive use
  • postmenopausal hormone use
  • changes in hormonal status

There are also four risk factors that are stronger or more prevalent in women:

  • migraine with aura
  • atrial fibrillation
  • diabetes
  • high blood pressure

Here are the new recommendations:

  • Women with a history of high blood pressure before pregnancy should be considered for low-dose aspirin and/or calcium supplement therapy to lower preeclampsia risks.
  • Women who have preeclampsia have twice the risk of stroke and a four-fold risk of high blood pressure later in life. Therefore, preeclampsia should be recognized as a risk factor well after pregnancy, and other risk factors such as smoking, high cholesterol, and obesity in these women should be treated early.
  • Pregnant women with moderately high blood pressure (150-159 mmHg/100-109 mmHg) may be considered for blood pressure medication, whereas expectant mothers with severe high blood pressure (160/110 mmHg or above) should be treated.
  • Women should be screened for high blood pressure before taking birth control pills because the combination raises stroke risks.
  • Women who have migraine headaches with aura should stop smoking to avoid higher stroke risks.
  • Women over age 75 should be screened for atrial fibrillation due to its link to higher stroke risk.

Women generally have lower blood pressure levels than men, but that changes with age. Intervention (treatment of hypertension) in women over 55 reduced strokes by 38% and heart attacks by 25%. The benefit of treatment is even greater in younger and black women. There is no evidence for sex differences in response to medications, and treatment recommendations are the same for both sexes; but in practice, there is a difference in the drugs men and women are given, and fewer women achieve good BP control.

In December 2013 a report from The Eighth Joint National Committee published in The Journal of the American Medical Association found that treatment goals for patients over 60 could be changed from 140/90 to 150/90 without changing outcomes. For patients under 60, they found insufficient evidence to support any systolic BP threshold for drug treatment. There was evidence to support a diastolic goal of less than 90 in those over 30. As with the recent cholesterol guidelines, clinicians are encouraged to make treatment decisions for individuals based on their overall risk status rather than treating to reach a specific BP or cholesterol level. They also stress the importance of prevention: “For all persons with hypertension, the potential benefits of a healthy diet, weight control, and regular exercise cannot be overemphasized.”

Mainstream medicine has always preferred prevention to treatment. For those who accuse doctors of just throwing pills at patients, here’s a quotation from the 2002 guidelines:

The continuing message is that adoption of healthy life habits remains the cornerstone of primary prevention, including the avoidance of tobacco (including secondhand smoke), healthy dietary patterns, weight control, and regular, appropriate exercise. An important role of healthcare providers is to support and reinforce these public health recommendations for all patients.

In the male-dominated fields of science and medicine, women have too often been given short shrift. The situation is radically different today from what it was when the women’s lib movement first started to raise our consciousness of gender inequities. As the Virginia Slims slogan said, “You’ve come a long way, baby” but we need to go still further. The new guidelines point out that risk assessment tables for cardiovascular disease are based largely on data from men; better data and new tables are needed to predict risk in women. I hope these new sex-specific guidelines will be the first of many such efforts, not just in cardiovascular disease but in every aspect of medicine.

Posted in: Public Health, Science and Medicine

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17 thoughts on “Different Strokes for Different Folks: Assessing Risk in Women

  1. rork says:

    “those guidelines said stroke was more prevalent in men than in women”
    I’m not sure that’s true, but it is a big document, and what “prevalent” means might be a bit touchy. The risk (hazard) for men could be higher in a model with age, sex, and other things in there, cause the frequency at any given age might be higher for men. That’s the kind of thing I see them saying:
    “age-adjusted male-to-female ratio decreasing from 1.11 to 1.03″ – the difference was getting smaller. On a per-person basis, women might stroke more, thanks to somewhat longer lives – that’s the kind of figures Hall was giving.

    1. rork says:

      Durn, they actually do say more prevalent in men, referring to a 2006 paper, and maybe it was true then. Sorry to jump in there too quickly. It may still be true today. The new paper does mention at least twice how an apparent paradox can happen, and it seems hazard may still be higher in men that women until perhaps age 85 – the literature is too big for complete review (by me).

      1. CHotel says:

        Rate of recurrent stroke may also impact the numbers. I’ve always known prevalence to mean the absolute number of events:

        (fictional numbers for recurrence)
        20 of 100 women have a stroke at some point, 3 of those have a second event.
        17 of 100 men have a stroke at some point, 7 have a second event.

        Women’s lifetime risk is higher (numbers from the guidelines as cited by Dr. Hall), but men’s prevalence is greater (24 vs 23 events). From the old guidelines, “The declines in stroke death rates, however, were greater in men than in women”

        It could also be that the two references for the prevalence statement in the old guideline are from 1989 and 1999.

  2. CHotel says:

    “It’s not just that one has dangly bits and the other has bumpy chests. Or that one has to shave a beard and doesn’t like to ask for directions while the other has menstrual periods and likes to discuss feelings.”

    Before I read the rest of the article, just want to say how much I love this. Cause it’s a lot.

    (Although, why would you shave a beard when you could not shave a beard instead? Then you’d have a sweet beard.)

    1. Bruce says:

      Because if you had sparse and blotchy facial hair like me, shaving is the only option!

      1. CHotel says:

        Perhaps I should appreciate my beardly gift more.

    2. mousethatroared says:

      How about if you have menstrual periods and hate to ask for directions? Worse of both worlds, I guess.

  3. mousethatroared says:

    Isn’t it a little cruel to run a column on strokes on Paczki Day? ;)

    I actually thought having a relative who had had a stroke would play in there somewhere, but it doesn’t look like it, unless you’ve inheritated the high BP or diabeties.

    1. Harriet Hall says:

      Family history is a risk factor for stroke. The new guidelines for women address risks specific to women or higher in women. The older guidelines for stroke list family history as one of the non-modifiable risk factors (for both sexes). Both guidelines emphasize the modifiable risk factors. You can’t change your genetic inheritance, but you can stop smoking and control blood pressure.

      1. mousethatroared says:

        Ah! That makes sense. Thanks Harriet.

    2. Angora Rabbit says:

      @Mouse: Isn’t it a little cruel to run a column on strokes on Paczki Day?

      Oh, geez, I’d forgot that was today! I gotta go find some, if they’re not gone already…

      1. Chris says:

        I read that and seriously thought it was either a victim of stroke, or a famous researcher on strokes. Now I have been educated by Google U. ;-)

        I confess one of the big days in our city is the 17th of May. Uff da!

        1. Calli Arcale says:

          Uff da? Are you thinking of Syttende Mai? ;-) Whereabouts are you?

  4. Definitely a long way to go, in research as well as provider education and clinical practice. A guideline may suggest weight loss, lifestyle or behavior change…..but all interventions are not created equal.

    In 2002, adopting a healthy lifestyle was recommended… hmm, but still such a long way to go! Recommending weight loss may not seem to border on paternalism, but, well, it kind of does when the skill set is absent.

    Two providers can both prescribe an anti-hypertensive and the intervention and outcome will be pretty equal.

    Engaging a patient in discussion regarding behaviors, guiding them through the change process in a stepwise fashion -as it relates to change readiness, and supporting patient self-efficacy is a far removed from “you need to lose weight.” Even when the data is there, the most effective road may not be the paved one or the one most travelled….outcome depends a lot on the skillset of the driver.

    Just as all guidelines are not always created equal, neither are provider interventions or….(wince) outcomes.

  5. Wow, this is so interesting to me, I’ve kind of got the opposite of your problem, my spine has almost no curve to it, and I’ve also been working with a PT to help with some of the tension this causes.

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