Dylan Collins | Vox

Doctors botch blood pressure readings more often than you think

2018-07-04T07:53:22-04:00

To get a correct blood pressure reading, patients need to be seated with their back supported and feet flat on the floor. But in practice doctors usually just measure while the patient sits hunched over on the bed with their feet dangling. | Getty Images

Picture the last time your doctor checked your blood pressure. Were you sitting in a chair? Were you relaxed? Were you silent? Did your doctor or nurse take more than one reading?

Chances are, the answer to one or more of these questions is “no” — which means there’s a good probability your blood pressure reading was wrong.

Blood pressure measurement is one of the most common and high-stakes tests in medicine. Getting it right can be a matter of life or death because high blood pressure leads to serious diseases like heart attacks, strokes, erectile dysfunction, even dementia. More than 1,100 people in the US die each day from diseases caused by high blood pressure, and one in five adults don’t know they have it. A faulty reading can mean not catching an early warning sign.

The American College of Cardiology and American Heart Association have guidelines with steps that health professionals are supposed to follow to get accurate measurements. But they are notoriously bad at sticking to them.

“We wouldn’t fly on a plane where the pilot said, ‘I’m going to ignore the guidelines I have for safe travel,” said Dr. Paul Whelton, a professor at Tulane University and chair of the writing committee for updated US guidelines on blood pressure. “But that’s exactly the situation we have today with respect to blood pressure measurement.”

The only way to know whether you have high blood pressure is by getting an accurate reading. Yet the current data suggests only half of people with high blood pressure in the United States are able to get their blood pressure under safe limits, in part because improper measurement of blood pressure leads to the wrong diagnosis.

That’s why US blood pressure guidelines were recently updated for the first time in 14 years. Among other changes, the guidelines double down on correct blood pressure measuring technique, recommend the use of automated blood pressure machines, and suggest measurements outside of the doctor’s office — all in the hopes of saving lives. It’s a significant moment in what’s now an international movement to take blood pressure more seriously.

There is reason for hope that health professionals in the US can do better. Just look to Canada, which now has the largest proportion of hypertensive patients with their blood pressure under control in the world. It wasn’t always that way — but the fact that they got there suggests other doctors and patients can too.

High blood pressure, explained

Blood pressure is the force that blood exerts on your arteries. With every contraction and relaxation of your heart, the pressure inside your arteries spikes (called systolic blood pressure) and then drops (diastolic blood pressure). A normal blood pressure range is less than 120 mmHg systolic and less than 80 mmHg diastolic — or less than “120 over 80.”

Blood pressure varies from hour-to-hour, day-to-day, and year-to-year. But stubbornly high blood pressure becomes dangerous because it can cause arteries to burst, get inflamed, or clog, leading to diseases like heart attacks, strokes, and heart failure.

Many factors come together to cause high blood pressure, some of which you can control and some you can’t. Age, sex, ethnicity, and other health conditions can all affect your risk of high blood pressure — but you can’t change them.

Physical activity, a diet with less salt and more vegetables, not smoking, and maintaining a healthy body weight though can all bring blood pressure down. So can medications in some cases.

Although cardiovascular diseases, like heart attacks and strokes, are still the No. 1 cause of death in the United States, they have drastically declined since the 1960s. This is thanks to public health officials targeting behaviors that are linked to developing these illnesses, including smoking, alcohol use, and eating trans fat. But there has been less success with reducing high blood pressure, a key risk factor for heart attacks and strokes.

Why doctors often fail to take correct blood pressure readings

There’s a whole slew of things health professionals are supposed to do to get accurate blood pressure readings, many of which are performed correctly: placing the cuff at the right location around your arm, holding your arm at the level of your heart, using a stethoscope to listen to the pulse, and making sure there is no clothing on your arm.

But other steps that require more time often get overlooked. These include making sure that you sit in a chair and relax for at least five minutes before the measurement, that you have an empty bladder, and repeating the process for a second measurement one or two minutes later.

Whelton thinks one big reason physicians haven’t done a good job of measuring blood pressure is that they are “stretched in many directions” and not incentivized to aim for precision. “So I don’t think there is anything malicious about it, but [doctors wrongly] assume, in many instances, they’re doing a great job,” Whelton said.

In my own experience as a medical student, I’ve noticed that taking blood pressure correctly is indeed a luxury of time — and despite their best intentions, overworked doctors are often too crunched and too distracted to bother with correct technique.

When researchers have compared the blood pressure readings that doctors record to the values obtained by nurses who are specifically trained to follow correct technique, the results are alarming. Casual measurements taken by doctors overestimate blood pressure by about 10 mmHg. That could be the difference between normal blood pressure (120 mmHg) and stage one hypertension (130 mmHg), according to newly updated US definitions.

How to take a correct blood pressure reading, according to the new, controversial guidelines

In hopes of finally changing the status quo — and reducing cardiovascular diseases — 2017 guidelines, published by the American College of Cardiology and the American Heart Association (in conjunction with nine other groups), just broadened the definition of hypertension.

For the first time ever, hypertension is now diagnosed at systolic blood pressures of 130 mmHg or higher, rather than 140 mmHg. This change means that an additional 31 million adults in the US are now considered hypertensive, and 4 million of these people qualify for medication to lower their blood pressure.

This also means accurate blood pressure measurement is more important than ever to identify and treat those at risk. To address this, the guidelines for doctors are clear: They recommend using automated blood pressure devices (rather than manual hand pump sphygmomanometers), averaging multiple readings, and measuring blood pressure outside of the clinic (“out-of-office” measurements), which, for most patients, can help increase the accuracy of blood pressure readings.

But most important is following correct technique when measuring blood pressure using a manual blood pressure device, for which the new US guidelines include a nearly 19-step checklist. Here are some of the other checklist items to follow before your doctor or nurse takes your blood pressure:

Sit in a chair with your feet on the floor for at least five minutes (sitting on the exam bed does not count) before the reading
Avoid caffeine, exercise, and smoking for 30 minutes before the measurement
Make sure your bladder is empty
Don’t talk during the measurement
A pressure reading initially should be taken in both arms, and future readings should be taken from the arm with the higher reading

For many years, blood pressure guidelines have recommended an average of two or more blood pressure readings on two or more occasions to get a correct measurement. They “underscored that recommendation” in the new guidelines, Whelton said.

Canada led the way with better methods of measuring blood pressure

Just because the blood pressure status quo hasn’t been improving lately doesn’t mean it won’t — and the Canadian example is instructive here.

In the 1980s and early 1990s, Canada was far behind the US in terms of properly diagnosing and managing hypertension. During that time, only 13 percent of Canadians with hypertension reached their blood pressure target, while this number was 25 percent in the US. Today, Canada is recognized as the world leader in lowering blood pressure, with 68 percent of hypertensive patients who have their blood pressure under control. (Today, about half of Americans have their hypertension controlled.)

While there are many differences between Canada and the US that could account for this gap, it’s worth noting that Canada embraced alternative forms of blood pressure measurement early on, like taking measurements outside of the doctor’s office with automated devices.

“Canada was one of the first [countries] to recommend out-of-office blood pressure measures,” said Dr. Nadia Khan, president of Hypertension Canada, the not-for-profit group responsible for blood pressure guidelines in Canada. “Out-of-office measures are much better at predicting future cardiovascular events than office blood pressures.”

The new US guidelines say much the same, which is one reason why, Khan remarked, the US is “moving closer to the Canadian approach.”

So the next time you head to the doctor’s office, it might be worth asking for a repeat measurement, a chair to sit on, or for your doctor to use a validated automated blood pressure monitor. Your life may depend on it.

Dylan Collins is a medical student at the University of British Columbia, and holds a PhD from Oxford University where he was a Rhodes Scholar. You can find him on Twitter @DylanRJCollins.

How PrEP, the pill to prevent HIV, may be fueling a rise in other STDs

2018-06-20T17:59:53-04:00

A systematic review published in March in the journal Clinical Infectious Diseases found that some PrEP users are having more risky sex — and as a result, getting more sexually transmitted infections. | Photo Illustration by Justin Sullivan/Getty Images

Boris*, a gay student in New York, went to his university health center in 2017 seeking a pill to prevent HIV. He was worried that condoms weren’t doing enough to keep him safe and had heard that pre-exposure prophylaxis or PrEP — the once-daily pill sold under the name Truvada — was a good idea for people with more than 10 sexual partners a year.

But his doctor was dubious about whether insurance should cover it, telling him, “I don’t know whether society should support the promiscuity of a few people.”

Even before PrEP hit the US market in 2012, there were fears that it would promote promiscuity, more risky sex, and unintended health consequences. The president of the AIDS Health Foundation called it a “party drug.” “Truvada Whore” emerged as a slut-shaming label for people who took it in the gay community.

Though some of those fears were tinged with moral judgement, there’s now data showing the concern about the health consequences is justified. A systematic review published in March in the journal Clinical Infectious Diseases found that some PrEP users are having more risky sex — and as a result, getting more sexually transmitted infections (STIs). The review, which brought together 17 studies on PrEP use and sexual behavior change, suggests that as people begin to trust PrEP, they’re having more condomless sex and worrying less about other STIs. The more recent studies in the review show the strongest trend.

It’s a timely finding for two reasons: PrEP is about to become more widely available, and cases of syphilis, gonorrhea, and chlamydia have lately been rising in the United States. Right now, PrEP is only available to people at the highest risk of getting HIV, including gay and bisexual men, people who engage in sex work, and people who use injection drugs. But the Food and Drug Administration just approved it for teenagers, and some experts think anybody who wants it should have access.

Though PrEP is only one of many reasons STIs are spiking, the early signs that people taking the pill are engaging in risky behavior suggests that traditional messages about condom use are failing. And it means the public health community needs to come up with better ways to help those at risk.

PrEP helps some people have more risky sex

The HIV/AIDS epidemic has killed 37 million people since it was officially recognized in 1981, but thanks to effective antiretroviral drugs, HIV is now a treatable chronic illness. Although gay and bisexual men account for just 2 percent of the population of the United States, they accounted for 70 percent of new HIV diagnoses in 2014. Recent estimates place the number of gay and bisexual men currently living with HIV in the United States at more than 600,000.

With the development of PrEP, people can take it and have sex with whomever they want, however they want, as much as they want, with essentially no risk of getting HIV. Let us be clear: PrEP is essential for fighting HIV. It works. It is safe. Researchers think it may already be helping to reduce the number of new HIV infections. But to date, the question of how PrEP is changing people’s sexual behaviors has been an open one.

That’s what makes this new systematic review so important. The researchers only looked at unblinded studies of PrEP, meaning that the study participants knew they were taking the medication. So in effect, this review is a synthesis of the early evidence on how PrEP might influence sexual behavior in the real world.

The authors found that in some studies, PrEP use was associated with a 9 percent increase in the amount of receptive anal sex without a condom with 10 or more partners, an 11 percent increase in the amount of sex without a condom with an HIV-positive person or with someone whose HIV status was unknown, and a 14 percent increase in people never using condoms during anal sex. These are all high-risk behaviors that increase the chances of getting HIV and other STIs.

But they didn’t find any changes in the number of people who had any sex without a condom, partly because so few participants started off using condoms all the time. And this is a key point: PrEP didn’t appear to change the number of people who have sex without a condom.

But among those who already used condoms intermittently, PrEP was associated with more condomless sex and things like bottoming (receptive anal sex) more often — which carries a much greater infection risk than topping (insertive anal sex). In other words, people who were already engaging in risky sex seemed to have more of it on PrEP.

What’s more, the researchers found the risk of getting an STI increased during the period that PrEP has been on the market. Studies from before 2016, when PrEP was just starting to be used, didn’t show any increase in STIs. When the review authors looked more closely at the recent studies, the ones whose last follow-up with study participants was after 2016, they found an astonishing effect: Those on PrEP have 1.5 times the odds of acquiring an STI like chlamydia, gonorrhea, and syphilis, compared to before they started taking PrEP.

“Studies that were conducted [more recently] and with longer follow-up time are the ones where we found the most evidence for an increase in risk,” said Michael Traeger, a researcher at the Burnet Institute in Melbourne, Australia, and the lead author of the study. “We refer to this as the normalization of PrEP over time.”

Boris, the college student in New York, told me about his experience using hookup apps like Grindr while on PrEP. He said that most people don’t seem to have hard and fast rules about condom use, and people were generally willing to use a condom if their partner wanted it. But he did say that he thinks that PrEP allows people to have more condomless sex, and even amongst his friend group, he noticed people who have started having more condomless sex while on PrEP.

“Just talking to people that I know, there are many more people now who have bareback sex because they’re on PrEP than there were five years ago,” Boris told me. “I would be incredibly surprised if there was no change in the frequency” of risky sex.

PrEP is only one contributor of many to the skyrocketing rates of sexually transmitted infections

The rising rates of STIs among men who have sex with men isn’t a new problem — it’s a trend that started before PrEP.

The rates of gonorrhea infection among men who have sex with men have been climbing from 3.9 percent in 1989 to 37.8 percent in 2016. In 2016 there were more than 2 million cases of syphilis, gonorrhea, and chlamydia in the United States — the highest cumulative number of cases the US has ever seen. In the same year, men who had sex with men accounted for 80 percent of all primary and secondary cases of syphilis.

Although researchers believe PrEP is a contributor, they haven’t been able to tease out the effect of PrEP from the effect of new hookup apps or the existing upward trend in STIs. “There is not much control data, so we can’t attribute it to PrEP alone,” Traeger, the new study’s lead author, told me. “So while I would say that PrEP is a contributor, it is not the only contributor.”

And while some worry that PrEP is the final license people needed to give up condoms, it’s also clear that sex without a condom was becoming more and more popular well before PrEP. So it’s difficult to tell in the context of clinical trials whether we’re seeing the continuation of this trend or a change in behavior from PrEP.

Yet despite skyrocketing rates of STIs, experts think condom use will continue to decline no matter what.

“We’ve held up a standard and applied it almost uniquely to gay men — this idea that you are supposed to use a condom for every sex act for your entire sexual lifetime,” said Jeffrey Crowley, former director of the White House Office of National AIDS Policy and a distinguished scholar at Georgetown University. “That is an unattainable standard.”

He went on: “I would say that no matter what we do, no matter how many resources we put into promoting condoms, which all remain very important, we’re still going to see a decline in condom use over time. That was even if we didn’t have PrEP.”

I asked Boris why he thought condom rates were declining. He told me that condom use seems to be correlated with the psychological nearness of the AIDS epidemic. “As time passes and HIV seems less scary, people are just less frightened into always using condoms,” he said.

While there is some truth to this — HIV is less scary than it used to be — it is still a chronic and potentially life-threatening illness. And although syphilis, gonorrhea, and chlamydia are curable with medicine, if left untreated, they can be seriously harmful. Infection with any one of these illnesses also increases your risk of acquiring other infections, including HIV, which isn’t something you want if you’re having risky sex.

So what we’re left with, post-PrEP, is a personal balancing act of risks and benefits. The medication offers additional safety from HIV infection, but it may lead some to more STIs.

PrEP needs to go hand in hand with better testing, treatment, and partner notification.

This is not to say that condoms aren’t an important tool for staying healthy. But according to Crowley, at a time where HIV can be prevented with a single daily pill, we need to move beyond expectations that men will use condoms all the time, given the fact that they are making educated choices about what is best for their health, and PrEP can prevent them from getting a life-threatening illness. “We — as people who say we care about them — we need to find better ways to value and respect the choices they’re making,” Crowley told me.

PrEP distribution needs to go hand in hand with rapid testing and treatment for infections like syphilis, gonorrhea, and chlamydia, and better education about the signs and symptoms of STIs. And we need modern methods of partner notification about STIs, like integrating anonymous notification systems into hookup apps like Grindr.

These strategies — rapid testing, treatment, and partner notification — worked well in curbing HIV infections, and they can be used to rein in the STI crisis. In fact, most people prescribed PrEP are required to undergo full STI screens every three months. If this requirement continues, the widespread distribution of PrEP could, in theory, help bring down the rates of STIs.

*Boris is a pseudonym used to protect his identity.

Dylan Collins is a Rhodes scholar who has a PhD in evidence-based medicine from Oxford University. He is currently training to be a physician in Vancouver.

The new global plan to eliminate the most harmful fat in food, explained

2018-05-14T10:38:56-04:00

Traditional sweets in Afghanistan like jelabi are still often fried in oils containing trans fats. | AFP/Getty Images

For the first time ever, global health officials have asked countries to completely banish an ingredient from the entire food supply.

The enemy is trans fats, found in cooking oils and butter alternatives like shortening and margarine. Denmark became the first country to eliminate them from its food supply in 2004, and since then, countries across Europe and North America, including the US, have followed suit. The battle was waged by public health officials in the face of decades of scientific research showing that eating trans fat is associated with an increased risk of coronary heart disease and heart attack.

But this push hasn’t been spread evenly around the world. In North Africa, the Middle East, and South Asia, partially hydrogenated cooking oils that contain trans fat are commonly used in the home and by street vendors for frying and baking. And trans fat is thought to be responsible for an estimated 500,000 premature deaths from cardiovascular disease every year worldwide, according to the World Health Organization.

Now, the WHO, along with the Bloomberg Philanthropies and the Gates Foundation-funded health nonprofit Resolve to Save Lives (an initiative of Vital Strategies), has set out to change that. On Monday, the agency launched Replace, a guide to eliminating trans fat from the global food supply by 2023. If successful, they say it could save more than 10 million lives worldwide by reducing cardiovascular disease.

“Trans fat is an unnecessary toxic chemical that kills,” said Dr. Tom Frieden, president and CEO of Resolve to Save Lives and a former director of the US Centers for Disease Control and Prevention, “and there’s no reason people around the world should continue to be exposed.”

This is also the first time the WHO has called for the global elimination of a risk factor for a chronic disease, Frieden added. The WHO “successfully led the elimination of other infectious diseases, such as smallpox and river blindness, but never before has the world set its sights on eliminating a noncommunicable disease.”

And that’s why this announcement is such a big deal. Chronic diseases, like heart disease and diabetes, are quickly outpacing infectious diseases as the leading killers in countries around the world.

“The WHO statement is an important recognition that eliminating trans fat can substantially reduce risk of death and suffering at little or no cost,” Walter Willett, a Harvard Chan School of Public Health professor who has studied the effects of trans fat, told Vox.

Whether countries follow the advice is another question, he added, since the WHO has no enforcement power.

To understand why the WHO is seeking to phase out a single food ingredient, you need to know what trans fat is, why it’s harmful, and why people around the world keep putting it in food. Here’s a quick primer.

Trans fats are cheap, artery-clogging oils and shortenings that are still used in many countries

Trans fatty acids, or trans fats, are a type of unsaturated fat that can occur naturally at very low levels in some meat and dairy products. But it’s the man-made kind, like partially hydrogenated oil, that’s the health concern.

These artificial trans fats occur when hydrogen is added to liquid vegetable oil, like corn, soy, or cottonseed oil, to make it solid (think shortening or margarine) through a process called hydrogenation.

Trans fats were popularized in the 1950s, and their uses slowly expanded until they were ubiquitous in the food supply. They were baked into muffins, cookies, pies, and pizzas. French fries were fried in them, and they were even used in coffee creamers and microwave popcorn.

The reasons for the popularity are simple: The oils were relatively inexpensive to produce compared with solid animal fats, they increased the shelf life of food, they tasted good, and — at a time when saturated fats in butter were vilified — they were billed as a healthy alternative. (Think margarine versus butter.)

But over the past couple of decades, evidence has been mounting that even a small amount of trans fat increases bad (LDL) cholesterol in the blood and decreases the amount of good (HDL) cholesterol — raising the risk of coronary heart disease and heart attacks.

As this 2006 research in the New England Journal of Medicine shows, for every 2 percent of calorie intake that comes from trans fats, a person’s heart disease risk increases by an incredible 23 percent. While there’s still some debate about the relative health merits of saturated and unsaturated fat, health experts now pretty unequivocally reject trans fat.

That’s why the Food and Drug Administration in the US has worked to phase trans fat out of the food supply. In 2006, the FDA required manufacturers to start labeling their foods with trans fat content information. By 2013, the agency tentatively determined that trans fat could no longer be considered safe for people to eat. And by 2015, it asked food manufacturers to remove trans fat from their products by 2018.

This policy brought the US in line with other countries that have already banned trans fat, including Denmark, Austria, Iceland, and Switzerland. And it came after a number of cities across the United States, starting with New York City, banned the use of this type of fat in restaurants. After these changes went into effect, researchers doing follow-up studies found a decrease in cardiovascular disease rates (more on that below).

But trans fats are still finding their way into baked goods, solid fats like ghee and shortening, and restaurant and street food in many places — especially low- and middle-income countries, where they haven’t been banned and cardiovascular disease rates are on the rise.

In just 20 years, ischemic heart disease and cerebrovascular disease — two types of cardiovascular disease that affect the heart and brain, respectively — leaped from the fourth and fifth leading cause of premature mortality to the first and second, respectively, bumping lower respiratory infections and neonatal preterm birth complications from the top killers globally. The majority of these deaths from cardiovascular disease, more than 75 percent, occur in low- and middle-income countries.

Not all of this disease burden can be explained by trans fat. But eliminating it would have an impact, said WHO Global Ambassador for Noncommunicable Diseases Michael Bloomberg in a statement. “Banning trans fats in New York City helped reduce the number of heart attacks without changing the taste or cost of food, and eliminating their use around the world can save millions of lives.”

University of North Carolina nutrition policy researcher Barry Popkin said the WHO is likely underestimating the impact trans fat elimination would have in Asia and Africa. “The proportion of energy from fats and oils in Asia and Africa is double that from Europe and the US and in many countries that are dominated by palm oil and partially hydrogenated oils,” he said. “In India alone, the fats used have as much as 45 to 50 percent trans fats. This compares with the much smaller proportion of trans fats in higher-income countries, and the effect that eliminating even this much smaller level of trans fats significantly improved health.”

To understand the potential impact of the WHO campaign, look at Denmark and New York

The new WHO action plan has six suggestions countries can follow to eliminate trans fats from their food supply. These include passing regulations or legislation to ban industrially processed trans fats, creating public awareness campaigns about their health harms, and enforcing the compliance of trans fat regulations. In other words, they’re encouraging low- and middle-income countries to go the way of Scandinavia and the US.

The impact could eventually be very large, and Denmark and New York show why.

Researchers who studied Denmark’s policy found that three years after it went into effect, the mortality rate from cardiovascular disease declined by an average of 14.2 deaths per 100,000 people per year relative to a control scenario showing what would have happened if Denmark didn’t introduce the policy.

In New York state, researchers looked at the impact of artificial trans fat restrictions. The main finding: The regulations reduced the cardiovascular death rate by 4.5 percent. Another study found hospital admissions for heart attack and stroke also declined by 6 percent in New York counties with trans fat restrictions compared to state counties without.

“There are billions of people around the world who are eating foods with trans fat, and they don’t know, leading to half a million deaths every year,” Resolve’s Frieden added. “That’s why a public health approach, through effective policies, can save the most lives.”

But not every country has the resources of Denmark or the US to follow through on a trans fat ban. And just because the WHO sent out these guidelines doesn’t mean we’ll see the results anytime soon. The recommendations are voluntary, and governments may not take them up. It’s impossible to crack down on individual food vendors, which is why countries need to pass regulations that eliminate trans fat from the manufacturing process or implement nationwide bans.

“I expect there will be some pushback from industries that are accustomed to use of trans fat-containing ingredients,” said Eric Brandt, a cardiovascular disease fellow at Yale University School of Medicine who studied the impact of New York’s trans fat ban. “Hopefully precedents set by companies in countries with trans fat restrictions already in place will ease these transitions.”

Even so, the Replace action plan is worth watching. It’s taking lessons from successes fighting tobacco, except in this case, the enemy is a dietary risk factor.

“A comprehensive approach to tobacco control allowed us to make more progress globally over the last decade than almost anyone thought possible,” Bloomberg said. “Now, a similar approach to trans fat can help us make that kind of progress against cardiovascular disease, another of the world’s leading causes of preventable death.”