Many patients have been asking me recently about news reports mentioning a study that linked testosterone to an increase in heart attacks in men. “Testosterone prescriptions linked to heart attack” was the headline in the Los Angeles Times on January 29, 2014.
Yikes! Of course this headline grabbed my attention.
The news reports stem from an article published in the journal Plos One, titled ‘Increased Risk of Non-Fatal Myocardial Infarction Following Testosterone Therapy Prescription in Men.’
So I looked closer at the study.
Before I talk about the serious flaws in the study, the first thing I should mention is this: Testosterone therapy is not to be taken lightly. With all the popularity of testosterone therapy these days, there are many doctors recklessly prescribing it without properly screening patients. There are “Low T” clinics sprouting up in strip malls across the country. This is has been, and continues to be, unsettling to me. Testosterone (or any hormone therapy) should be properly prescribed and and monitored by a hormone specialist. If you think you may benefit from testosterone, see a hormone specialist who will comprehensively evaluate you. He or she should be well versed in the benefits and risks of therapy and the treatment of possible side effects for you to have optimal benefits from the therapy.
Now, as for the Plos One study, here are the important problems:
This is an observational study. These are the ones that typically make news headlines, as one can observe any outcome and draw erroneous conclusions from it. It is not a randomized trial. Most of the randomized, controlled studies on testosterone demonstrate considerable cardiovascular protection (more later). If you manipulate the data of any study long enough, you can get it show anything that you want.
The study did not assess testosterone levels of patients before and during therapy. It looked at men who filled a prescription for testosterone. Not even whether or not they took it, or took it correctly. Without proper assessment of testosterone levels, it is impossible to tell if a patient is a good candidate for therapy or if they are tolerating the therapy well. And without knowing if the men took their testosterone, or took it correctly, you need to be very wary of conclusions drawn. This is very basic stuff when if comes to research studies.
The biggest problem with this study has to do with the “control group.” The authors compared the groups of men who were prescribed testosterone therapy to men who were prescribed a class of drugs called PDE5 inhibitors. You’ve heard of these drugs before by their brand names: Viagra and Cialis. The authors observed a lower risk of heart disease in the PDE5 inhibitor group. PDE5 inhibitors are drugs typically used to treat men with erectile dysfunction. The authors state they used this group “as comparison” to the testosterone group so there would theoretically be an increase in sexual activity in both groups.
But they ignored an important fact! PDE5 inhibitors have significant positive effects on the cardiovascular system. Two PDE5 inhibitors have even recently been approved for treatment of idiopathic pulmonary hypertension because of their ability to relax blood vessels. And a new study in the Journal of Cardiovascular Pharmacology and Therapeutics states that PDE5 inhibitors have potential as cardiovascular drugs in patients with coronary artery disease and in heart failure patients.
If PDE5 inhibitors can decrease the risk of heart disease and relax blood vessels in men with heart disease, how can the authors of this study possibly think that men on PDE5 inhibitors would be a good control group against the men placed on testosterone?
The results of the Plos One study run counter to an overwhelming amount of literature over 25 years that supports the use of testosterone as an important therapy that can lower cholesterol and blood sugar levels, reduce body fat and increase lean muscle mass. These are all factors that reduce the risk of heart disease.
A new review article published in December 2013 in the Journal of the American Heart Association (JAHA) provides a comprehensive review of the clinical literature looking at associations between testosterone and cardiovascular disease. Over 100 studies were reviewed, and the authors concluded that low levels of testosterone are associated with increased rates of overall mortality, cardiovascular-related mortality, and higher rates of obesity and diabetes. And the severity of disease correlated with the degree of testosterone deficiency. Testosterone has been shown to relax coronary arteries and improve ability of patients with congestive heart failure to exercise. Testosterone lowers blood sugar in diabetics and lowers body mass index (BMI) in obese patients. Finally, studies have associated lower testosterone levels with thicker walls of major arteries, increasing risk of atherosclerosis. All of these factors point to the conclusion that optimal testosterone levels decrease the risk of cardiovascular disease.
The results of the current study, despite all the media coverage, are essentially meaningless. Testosterone therapy can be an excellent way to help men to improve their quality of life and decrease their risk of multiple diseases. This is shown in the overwhelming majority of studies.
Again, be wary of news headlines. Consult with a hormone specialist.
Show your doctor this blog post, especially if he or she tells you testosterone is going to increase your risk for heart attack. The truth is, you probably know more than he or she does about this study after reading this.