1. This placebo-controlled, double-blind trial showed that in older men (³65 years old) with low measured testosterone, one year of testosterone administration increased volumetric bone mineral density and estimated bone strength in trabecular and peripheral bones.
2. While the significant increase in bone density was a positive finding, the clinical outcome of importance, as measured by fracture rate, remains to be studied.
Evidence Rating Level: 2 (Good)
Study Rundown: Decreases in bone mineral density (BMD) are associated with increased risk of fracture. Akin to women, men also experience decreases in serum testosterone as they age and this has been associated with decreased BMD. It is unclear if the administration of testosterone in men with low levels can reverse the decrease in BMD. This study aimed to determine whether testosterone administation in older men with low testosterone levels increased volumetric BMD (vBMD) and estimated bone strength.
In this non-randomized, placebo-controlled, double-blind study, one year of testosterone administration was associated with significantly greater increases in both vBMD and estimated bone strength of the mean spine trabecular, spine peripheral, hip trabecular and peripheral bones. Estimated increases in bone strength were greater in the trabecular as compared to the peripheral bone, and also greater in the spine than the hip. Adverse events were similar across groups. Strengths of this study included the double-blind design, and participant retention. However, this was not a randomized study and did not look at the clinically-important outcome of fracture rate. Additionally, a longer study would be necessary to study sustained results.
Relevant Reading: Long-term changes in bone mineral density and predicted fracture risk in patients receiving androgen-deprivation therapy for prostate cancer, with stratification of treatment based on presenting values
In-Depth [controlled clinical trial]: This non-randomized, placebo-controlled, double-blind study was conducted at 9 US academic medical centers from December 2011 to June 2014. It included participants from the Testosterone Trials: men 65 years or older with two testosterone concentrations averaging less than 275 ng/L on two separate occasions. Exclusion criteria included presence of increased risk to conditions that testosterone treatment may exacerbate, or if participants were taking medications that affected bone health (other than over the counter calcium or vitamin D). These men were allocated into groups by minimization to either receive testosterone or placebo gel for one year. The testosterone gel doses were increased to ensure men maintained serum levels within normal range. All participants were supplemented with calcium and vitamin D. The main outcome of interest was spine and hip vBMD determined by quantitative CT at baseline and at 12 months. Bone strength was determined by analysis of CT data. Data was analyzed under a modified intention-to-treat protocol, with multivariable regression.
There were 211 participants allocated: 104 to receive testosterone, 85 allocated to receive placebo. Testosterone treatment increased mean lumbar spine trabecular vBMD by 7.5% (95% CI 4.8%-10.3%) as compared to 0.8% with placebo (95% CI 4.8%-8.7%; p < 0.001). Testosterone treatment also increased peripheral and whole bone vBMD of the spine and trabecular, peripheral whole bone vBMD of the hip. Magnitudes of changes were greater in the spine than in the hip. Estimated strength of spine trabecular bone was also increased in the testosterone group (10.8%; 95% CI 7.4%-14.3%; p < 0.001) as compared to placebo group (2.4%; 95% CI -1.0% to 5.7%). There were 6 fractures reported in each treatment arm over the year of study.
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