Target Health Blog

Mixed Results of Trials of Testosterone Therapy in Older Men

March 6, 2017

Men's Health

Recent studies have yielded conflicting results as to whether testosterone treatment increases cardiovascular risk and/or slows down the rate of cognitive function decline with age. As a result, two studies (Testosterone Treatment and Cognitive Function in Older Men With Low Testosterone and Age-Associated Memory Impairment; Testosterone Treatment and Coronary Artery Plaque Volume in Older Men With Low Testosterone); were reported on 21 February 2017 in JAMA, which tested the hypotheses as to whether testosterone treatment of older men with low testosterone 1) slows progression of noncalcified coronary artery plaque volume and 2) is associated with improved verbal memory and other cognitive functions and age-associated memory impairment (AAMI).

The clinical trials were conducted at 12 sites across the country in 790 men age 65 and older with low levels of testosterone and symptoms to which low testosterone might contribute. The studies were funded primarily by the National Institute on Aging (NIA), part of the National Institutes of Health. Additional funding came from the National Heart, Lung, and Blood Institute, the National Institute of Neurological Disorders and Stroke, and the Eunice Kennedy Shriver National Institute of Child Health and Human Development, all part of NIH. Additional funding, and the study drug and placebo, were provided by AbbVie Pharmaceuticals.

Study participants were randomly assigned to receive testosterone gel or a placebo gel applied to the skin daily. Serum testosterone concentration was measured at one, two, three, six, nine and 12 months. The men were also closely monitored for prostate and cardiovascular problems. In addition to low testosterone, the presence of complaints such as low sexual function, difficulty in walking or low vitality was required for eligibility to participate in the trials. The results of these outcomes were reported in 2016. The study also measured testosterone treatment’s effects on additional outcomes in the study population, which are reported in the current publications:

Anemia Trial

Of all the men enrolled, 64 had anemia from known causes and 62 had unexplained anemia. After one year of treatment, 54% of the men with unexplained anemia and 52% of those with anemia from known causes had clinically significant increases in hemoglobin (red blood cell) levels, compared with 15% and 12%, respectively, of those in the placebo group. These changes may be of clinical significance, as suggested by the magnitude of the changes, the correction of anemia in the majority of men, and the association of the increases with improvements in global impression of change in overall health and energy. Measurement of testosterone might be considered in men age 65 and older who have unexplained anemia and symptoms suggestive of low testosterone levels.

Bone Trial

The goal of this trial was to determine whether testosterone treatment would increase volumetric bone mineral density (vBMD) — the amount of mineral in bone —   and estimated bone strength in older men with low testosterone. Results showed that vBMD, a marker of increased risk for fractures, was measured in hip and spine at baseline and 12 months later. After one year of treatment, older men with low T significantly increased vBMD and estimated bone strength compared to controls, more so in the spine than in the hip. A larger and longer trial would be needed to determine if testosterone treatment reduces fracture risk.

Cardiovascular Trial

The study assessed the effects of testosterone treatment on the progression of noncalcified coronary artery plaque — a build-up within  the walls of the blood vessels in the heart — which is a risk factor for cardiovascular disease. The study found that noncalcified plaque volume increased significantly more in the testosterone-treated group compared to controls, as measured by coronary computerized tomographic arteriography, a special type of heart scan. The authors note that, because just 170 men had the scans, the clinical importance is uncertain and may depend on how testosterone affects different components of plaque. A larger and longer trial is needed to establish the clinical significance of these findings.

Cognition Trial

This trial sought to determine if testosterone treatment improved cognition in older men with age-associated memory impairment (AAMI), a mild form of impairment, distinct from dementia. Of the initial participants, 493 met the criteria for AAMI. After one year of treatment, there was no significant change in either the treatment or the placebo group in verbal memory, visual memory, executive function and spatial ability.

According to the authors, the results on diverse outcomes indicate the potential trade-offs between benefits and risks of testosterone treatment in older men. However, clarifying the effects of testosterone on many major clinical outcomes such as cardiovascular events, fractures, and disability will require longer, larger scale trials. The authors added that the results also illustrate that decisions about testosterone treatment need to be individualized, taking into account each patient’s balance of risks for the various conditions that testosterone treatment could affect.

The U.S. Food and Drug Administration has additional information about testosterone.

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