Testosterone Deficiency – aka “Low T”

shutterstock_148300076Low testosterone is a hot topic right now in primary care.  Recent advertisements are on television discussing various testosterone treatments available to men with “Low T.”  I’ve recently had quite a few patients asking me to check testosterone levels and then they usually have questions about testosterone treatments if the blood levels are abnormal.

Testosterone is a hormone that is produced in both men and women, but it is usually present at higher levels in men.  The consequences of low serum testosterone are not known for certain but there are several possible symptoms of low levels including (research is still being done):

  1. Low sex drive, erectile dysfunction, poor morning erection
  2. Fatigue
  3. Being slow to go through puberty (if it is too low during childhood)
  4. Decreased bone mineral density
  5. Decreased muscle mass
  6. Decreased muscle strength
  7. Anemia
  8. Decreased mood
  9. Decreased cognitive function

Of course there are other, more common causes of low sex drive and fatigue that can affect grown men instead of low testosterone levels.  Experts believe that the current trials have demonstrated weak and indirect inferences about the usefulness of testosterone for osteoporosis in men.

Testosterone levels naturally decrease as men age.  This normal decline in testosterone however has not had established clinical consequences.  We are still studying the effect that the natural decline of testosterone levels have in the body.  Elderly men often ask if they should be prescribed supplemental testosterone to keep their levels from decreasing.  The answer is difficult because we currently do not entirely understand whether the changes in body generally associated with aging (decreased muscle mass, decreased energy) may be related to naturally decreasing testosterone levels or even if treatment with testosterone reverses the decreasing muscle mass and energy we see in the average person with increasing age.  We’re also concerned about adverse consequences of testosterone with diseases that are testosterone dependent such as prostate cancer.

Controversy regarding testosterone whether to prescribe testosterone therapy:  A committee of the Institute of Medicine of the National Academy of Sciences Committee reviewed available studies and concluded that no beneficial effects of administering testosterone have been well established.  The Endocrine Society however has published evidence based guidelines for testosterone therapy in adult men with deficiency of testosterone.  The guidelines from the Endocrine society are:

  1. Testosterone therapy should be prescribed only for men with low serum testosterone levels on more than one test and who have symptoms of testosterone deficiency and have no known pituitary or testicular disease.
  2. In order to minimize the potential risk of causing testosterone-dependent diseases, the target level of testosterone level in the blood should be between 300-400 ng/dL (10.4 to 13.9 nmol/L)

The Institute of Medicine’s committee on testosterone concluded that there is insufficient evidence to conclude that testosterone treatment of elderly men has any well-established benefit thus far on improving muscle strength, physical function, vitality, sexual function, cognition and quality of life.  They recommended further investigation.

Potential to cause harm:  High testosterone levels has the potential to cause cancer of the prostate but data are limited.  The common practice in treating prostate cancer is to lower serum testosterone levels with medications.

Screening for low testosterone:  One approach has been the following:

  1. If a male has symptoms of possible testosterone deficiency such as decreased sex drive, energy, mood or osteoporosis or anemia a serum testosterone level can be checked early in the morning (before 8am when normal testosterone levels are highest).  If the level is low, it should be repeated for confirmation.
  2. Free testosterone levels should only be evaluated in men who have obesity.
  3. If testosterone levels (both times) is less than 200 ng/dL (6.9 nmol/L) evaluation for causes of hypogonadism can be performed. If there is no pituitary or testicular disease, discuss  with the patient about possible treatment with supplemental testosterone (ie. Benefits vs risks).

Testosterone treatment:  One approach to treatment has been the following:

  1. If treatment is started and the symptoms that led to measuring the testosterone are not corrected (improved energy, sex drive, anemia, etc.)  within a few months then discontinuing the testosterone treatment can be considered.
  2. Before starting treatment, a digital rectal exam should be performed and a PSA (prostate specific antigen) measured.  If a man has higher than normal PSA with no identifiable risk factors a urological evaluation should be performed before any testosterone therapy is started.
  3. 3 months after starting the testosterone treatment, a digital rectal exam and PSA should be repeated.  If there is a prostate nodule or the PSA has increased more than 1.4ng/mL (and confirmed) urological consult should be sought.  If the PSA and digital rectal exam is not considered abnormal, the digital rectal exam and PSA should be performed once a year  (just as with any man).

References:  Bhasin S, Cunningham GR, Hayes FJ, Matsumoto AM, Snyder PJ, Swerdloff RS, Montori VM, Task Force, Endocrine Society. Testosterone therapy in men with androgen deficiency syndromes: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 2010 Jun;95(6):2536-59.

This document is for informational purposes only, and should not be considered medical advice for any individual patient.  If you have questions please contact your medical provider.

 

I hope that you have found this information useful.  Wishing you the best of health,

Scott Rennie, DO

Blog: https://doctorrennie.wordpress.com

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