How well informed are general practitioners and cardiologists about testosterone deficiency and its consequences?

A rapidly growing body of medical research is showing that testosterone deficiency (aka hypogonadism and low-T) is strongly associated with a wide range of detrimental health outcomes^1,2, and that testosterone replacement therapy improves those health parameters that are negatively affected by testosterone deficiency.^2,3 Therefore, leading testosterone scientists now view testosterone deficiency as a cardiovascular risk factor that contributes to the development of cardiovascular disease.^4-7

As general practitioners and cardiologists primarily care for these patients with cardiovascular disease, a survey study was conducted to assess their knowledge, beliefs and clinical practice with respect to testosterone deficiency and cardiovascular health.⁸

A questionnaire was distributed to 20 cardiologists and 128 family practitioners in British Columbia, Canada. Of the 13 questions, 10 assessed knowledge and beliefs on testosterone deficiency and 3 assessed current practice patterns.⁸

KEY POINTS

Most general practitioners and cardiologists believed that hypogonadism is a medical condition (66.7%) and could negatively affect body composition (62%), but a similar majority was unsure whether it was a cardiac risk factor (66.7%).
While most believed that testosterone replacement therapy could improve exercise tolerance (62%), most were unsure if it was beneficial in cardiac patients.
Cardiologists were significantly less likely to believe that testosterone deficiency was beneficial in preventing recurrent heart attack (myocardial infarction) and improving oxygen supply to the heart (myocardial perfusion).
Over half of the respondents (58.8%) said they were unsure whether testosterone deficiency could contribute to low HDL (high-density lipoprotein, the “good” cholesterol) levels.
The vast majority (88%) of general practitioners and cardiologists did not screen their cardiac patients for testosterone deficiency. If a patient was identified as having hypogonadism, only 23.5% would treat the patient themselves, and 27.5% would refer to an endocrinologist.

What is known

Testosterone deficiency is an acknowledged cardiovascular risk factor among leading hypogonadism researchers.^4-7

Studies show that testosterone replacement therapy improves exercise tolerance in both healthy men⁹ and in cardiac patients.^10-12 In fact, cardiac patients are the ones to benefit the most. Several studies shows that in men with known angina by treadmill testing, testosterone replacement therapy significantly increases time to ischemia.^10-12 These results are consistent with other studies in humans in which testosterone administration has been shown to induce vasodilation of the coronary¹³ and brachial arteries.^14,15 Testosterone therapy also benefits men with congestive heart failure by significantly improving performance in the 6 minute walk test, incremental shuttle walk test, and/or peak oxygen consumption, and overall exercise capacity, compared to placebo.^16-20 No significant adverse cardiovascular events were noted.^16-18 Two additional, more recent placebo-controlled trials have confirmed beneficial functional effects of testosterone therapy in men with congestive heart failure.^21,22

It is also documented that testosterone deficiency is associated with reduced HDL levels²³, and that physiological restoration of testosterone levels with testosterone replacement therapy increases HDL levels, in addition to reducing fasting blood glucose, insulin resistance, triglycerides (blood fats), and waist circumference.^24-31

TRT was associated with a significant reduction of fasting plasma glucose, homeostatic model assessment index, triglycerides, and waist circumference. In addition, an increase of high-density lipoprotein cholesterol was also observed.

What this study adds

Despite its high prevalence in cardiac patients, testosterone deficiency is not well-understood by general practitioners and cardiologists; they lack knowledge on its deleterious cardiovascular effects.⁸

The survey results presented here clearly show that the large majority of primary care physicians and cardiologists need more information about the health consequences of testosterone deficiency, as well as the benefits of testosterone therapy.

The finding that most primary care physicians and cardiologists do not screen their patients for testosterone deficiency is a red flag, as the prevalence of obesity, metabolic syndrome and diabetes is epidemic in today’s society, and it is well documented that testosterone deficiency in men with those conditions is extraordinary common, regardless of age. Specifically, in those men, the prevalence of testosterone deficiency ranges from 35% to almost 80%.^32-36

A limitation of this study is that it was a relatively small survey from a Canadian province, and its results may not be the same in other areas of the world. However, other surveys of doctors from countries across the world reported many similarities in their approach to diagnosis and treatment of hypogonadism, and their beliefs about alleged risks (especially prostate and cardiovascular issues).^37,38

The results from this survey underscore the importance for men to be pro-active about their own health and specifically request testing for testosterone deficiency if they are having symptoms/signs of hypogonadism.

In a sense, every man, even the young and healthy, should have his testosterone levels checked (plus SHBG, PSA, at a minimum) just to establish his healthy baseline. This is important because relative changes in testosterone levels over time may be a better predictor of impending testosterone deficiency and health deterioration than are the actual levels of total testosterone and/or free or bioavailable testosterone.³⁹

Also, because the testosterone reference range is quite wide, every man needs to find his own optimal testosterone level. The reference range for total spans all the way from approximately 350 to 1200 ng/dL⁴⁰. This wide range leaves a lot of room for expression of individual variation, i.e. significant decreases in testosterone levels that are still within the reference range. For example, a 50% decrease in testosterone levels will likely negatively impact most men. However, if a man’s healthy optimal baseline is in the upper end of the reference range, let’s say 1000 ng/dL, him reaching 500 mg/dL will not qualify for hypogonadism diagnosis if the current diagnostic criteria are used, which define biochemical hypogonadism as a total testosterone level below 300 ng/dL (US Endocrine Society)⁴¹ or below 350 ng/dL (European Association of Urology Guidelines).⁴²

Finding your optimal healthy baseline testosterone level can only be done via regular blood testing, staring early in life. This will provide an invaluable personal benchmark against which to track hormonal changes over time.

References

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