By Chris Kaiser, Cardiology Editor, MedPage Today
Published: March 22, 2013
Energy drinks may raise blood pressure and interfere with the heart's electrical system, increasing the risk of sudden cardiac death, a meta-analysis found.
In a pooled analysis of 93 people who consumed energy drinks, the QT interval – a segment of the heart's rhythm on an ECG – was significantly prolonged by 10 ms, according to Sachin A. Shah, PharmD, from the University of the Pacific in Stockton, Calif., and colleagues.
In another pooled analysis of 132 people, researchers found a significant increase in systolic blood pressure by 3.5 mmHg that was associated with the consumption of energy drinks, Shah reported at the American Heart Association Epidemiology and Prevention/Nutrition, Physical Activity and Metabolism 2013 meeting in New Orleans.
Diastolic blood pressure and heart rate were not significantly increased but Shah and colleagues said that the QT prolongation and increase in systolic blood pressure were maintained in most subgroup sensitivity analyses.
“Doctors are generally concerned if patients experience an additional 30 ms in their QT interval from baseline,” Shah said in a statement.
His co-author Ian Riddock, MD, from David Grant USAF Medical Center in Travis Air Force Base, Calif., added, “QT prolongation is associated with life-threatening arrhythmias. The finding that energy drinks could prolong the QT, in light of the reports of sudden cardiac death, warrants further investigation.”
The seven pooled studies included healthy, young participants whose ages ranged from 18 to 45.
A previous review in the journal Pediatrics found that nearly half of the more than 5,000 caffeine overdoses reported in 2007 involved people under age 19. The review noted that up to half of the energy drinks on the market are consumed by adolescents and young adults.
The FDA has initiated several probes into energy drinks after reports of deaths were preliminarily linked to the drinks.
Drinks such as Monster, Red Bull, Rockstar, Full Throttle, and AMP have three times the amount of caffeine as colas. A 16-oz. can of Monster Energy, for example, contains 160 mg of caffeine, which is almost as much as five cans of soda.
Since 2005, the FDA has required drugs to be evaluated in a Thorough QT (TQT) study to determine their effect on the QT interval.
“The threshold level of regulatory concern is around 5 ms,” according to the 20-page “Guidance for Industry” on how to conduct “Clinical Evaluation of QT/QTc Interval Prolongation,” published by the FDA.
But the FDA can do nothing about the observed 10 ms increase in QT interval found by Shah and colleagues in this meta-analysis.
“Although the U.S. Food and Drug Administration limits caffeine content in soft drinks, which are categorized as food, there is no such regulation of energy drinks, which are classified as dietary supplements,” the authors of the review in Pediatrics wrote.
Energy drinks capture 47% of the beverage market share internationally, Shah and colleagues noted. They said a general consensus on how to evaluate the health risks of energy drink consumption does not exist.
They therefore sought to determine the specific effect of energy drinks on “notable electrocardiographic and blood pressure parameters.”
Researchers included data from seven previously published observational and interventional studies.
They said that further safety evaluation of energy drink consumption is warranted to guide public health policy.
Researchers reported they had no conflicts of interest.
Primary source: AHA Epidemiology and Prevention/Nutrition, Physical Activity and Metabolism
Source reference:
Shah SA, et al “Impact of energy drinks on electrocardiographic and blood pressure parameters: a meta-analysis of clinical studies” EPI/NPAM 2013; Abstract P324.
http://www.medpagetoday.com/Cardiology/Arrhythmias/38020
