Chewing Khat Increases Risk in Cardiac Patients

December 12, 2011

December 12, 2011 (Doha, Qatar) — Chewing khat, the leaves of the Catha edulis plant, a common practice in Yemen and certain East African countries, increases the risk of death and stroke in patients presenting with acute coronary syndrome (ACS), a new observational study by Dr Waleed M Ali (Hamad Medical Corp, Qatar) and colleagues shows [1].

But users and physicians do not always appreciate the risks of this compound because it is often considered to be "herbal," senior author Dr Jassim Al Suwaidi (Hamad General Hospital, Doha, Qatar) told heartwire . Khat is far from benign, however; one of the main components is cathinone, which is almost identical in structure to amphetamine and functionally similar to amphetamine, cocaine, and methylenedioxymethamphetamine (MDMA); it also contains norephedrine, says Al Suwaidi.

[Khat users] are young and old, men and women.

And he stresses that what was once a problem of the developing world is now a global issue, due to widespread immigration. Doctors everywhere need to familiarize themselves with the risks associated with khat use, warn users of the dangers, and counsel against this practice, he says. "Physicians in general and cardiologists need to know about local practices that are no longer local but are spreading everywhere. When a patient comes to you from certain parts of the world, you need to be aware that khat use may have harmful effects."

And Al Suwaidi warns that khat users do not fit the usual profile of recreational drug users. "They are young and old, men and women; it's a culturally acceptable type of thing" in certain countries, including Yemen, Ethiopia, Somalia, and Kenya.

Chewing Khat in Middle East Dates Back to Ancient Times; Now It's Gone Global

Chewing khat--which is also known as mirra, qat, chat, and quaadka--dates back to times of antiquity and may predate the use of coffee, say Ali et al in their paper.

Unlike other substances of abuse, khat is highly perishable: the leaves are stripped from the trees early in the morning, and for this reason its use was initially thought to be of limited concern to Western populations, but overnight-delivery systems and emigration of people from countries where use is high have meant the practice of chewing khat has gone global. Seven metric tons of khat are estimated to travel through Heathrow Airport in London every week, originating from Yemen and the Horn of Africa, say the researchers.

In Yemen, chewing khat is legal, and it is estimated that around 60% of the population uses it. Ethiopians, Somalis, and Kenyans also use khat to a similar extent, and emigrants have also developed a form of dried khat, known as graba, which has high amounts of cathinone in it. And Jewish people from these countries moving to Israel have developed synthetic forms of khat known as hagigat, rakefet, mephedrone, or meow meow, says Al Suwaidi.

Almost 20% of Study ACS Population in Middle East Were Khat Chewers

In their study, Ali and colleagues enrolled 7399 consecutive patients with confirmed ACS presenting at 65 hospitals in six countries--Bahrain, Saudi Arabia, Qatar, Oman, United Arab Emirates, and Yemen--in the second Gulf Registry of Acute Coronary Events (Gulf RACE-2). "We compared those who had used khat with those who had not," explains Al Suwaidi.

It's legal and culturally acceptable to use khat; it's a Yemeni habit.

Of the patients, 19% were khat chewers, and the majority of khat users (>90%) were from Yemen, where "it's legal and culturally acceptable to use khat; it's a Yemeni habit," notes Al Suwaidi. He adds that use of khat is not legal in the other countries in which the study was carried out, so even if people were using it they may have been afraid to reveal the fact. In the study, 21% of the overall population were women, and 14% of khat users were women.

Largest Study to Date Evaluating Khat Use Among ACS Patients

Khat chewing was associated with a higher rate of mortality and of complications such as cardiogenic shock, heart failure, recurrent ischemia, arrhythmias, and stroke, despite a lower prevalence of cardiovascular risk factors among khat users. Al Suwaidi said khat users were less likely than nonusers to have diabetes, dyslipidemia, or hypertension, but they were more likely to smoke than nonusers.

In-hospital mortality was 7.5% among khat chewers compared with 3.8% of non-khat chewers (p<0.001), and mortality at one month (15.5% vs 6.4%) and one year (18.8% vs 10.8%) was also higher among khat users. Multivariate adjusted figures showed no increased risk of in-hospital mortality among khat users, but a higher death rate at one month (odds ratio 1.69; p<0.005) and one year (OR 1.46; p<0.005) compared with non-khat users.

Because the study was observational, there are no data on which patients continued to use khat or whether physicians counseled patients to stop using khat, says Al Suwaidi.

The researchers say they have previously reported that khat chewing was associated with worse outcomes in patients with ACS, and there have been reports of heart attacks and strokes in patients in the West taking khat. But the present study "is the largest . . . that evaluates the clinical characteristics, therapy, and outcome of khat-chewing ACS patients to date."

Thrombolysis and Beta Blockers Safe to Use in Khat Chewers

Al Suwaidi told heartwire that although cardiologists are always concerned about using beta blockers and thrombolytic therapy in people who abuse cocaine and amphetamines, the new study showed that these two approaches appear to be safe to use in khat chewers,

"It looks like those [khat users] who had beta blockers had better outcomes than those that did not get beta blockers, which is also consistent with recent literature about the use of beta blockers and cocaine," he notes. Those who were on beta blockers at discharge also appeared to fare better longer term than those who were not taking them, he noted. Given that the constituents of khat increase heart rate and blood pressure, this finding is perhaps not surprising, he observes.

"And thrombolysis appears to be safe" in khat users, he adds, although he acknowledges, as an interventional cardiologist, he feels that PCI for ACS "is always better than thrombolysis. But if you go to the real world, if you go to certain countries like Yemen, PCI is not an option. Then you think about thrombolysis."

Much More Research Needed

If you have a patient coming from Yemen or the east Horn of Africa, you should ask them about the use of khat on admission and counsel them against using it.

"This paper is really just raising a red flag for physicians, cardiologists, and ER doctors," says Al Suwaidi. "If you have a patient coming from certain parts of the world, specifically Yemen or the eastern Horn of Africa, you should ask them about the use of khat on admission, and you should counsel them on discharge against using it, because there is a lack of awareness among people; they think it's this herb thing," he reiterates.

And he stresses that that much more research needs to be performed to better understand this phenomenon. "We need many more studies. For example, comparing those who continue to use khat with those who don't, looking at the amount of khat being used--because its deleterious effects are dose-related--and also looking at specific types of khat, because there are 10 or 12 types of khat trees containing various amounts of cathinone."


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