Testosterone therapy may be warranted to improve mobility in older men with low levels of the hormone, a new analysis of the Testosterone Trials (TTrials) shows.
While the previously reported primary analysis of TTrials data in men with limited mobility showed little or no physical function gains with testosterone, a secondary analysis has shown benefits did occur in other men taking part in the series of trials, particularly those who had a higher baseline gait speed.
Published in the Lancet Diabetes Endocrinology, the new analysis shows that testosterone consistently improved walking ability, modestly improved performance on the 6 minute walk test (6MWT) distance but did not affect falls.
The original study randomised 790 men over 65 with testosterone levels below 9.5nmol/L to treatment with testosterone 1% gel daily or placebo, of whom 390 had mobility limitation.
New analyses shows that those not originally enrolled in the physical function test arm of the trials had 6MWT distance improved by 8.9m and also had a significant improvement in physical function as assessed by the physical function component (PF10) of the Medical Outcomes Study Short Form-36.
The improvements in walking test scores and physical function were significantly greater among men who had a baseline walking speed of 1.2m/s or higher.
Men reporting mobility limitation also had significantly more improvement in the 6MWT distance with testosterone. Testosterone use was also associated with higher rates of self-reported perception of improvement in walking ability compared to placebo.
An accompanying commentary said the unexpected findings of greater treatment effect in men with better baseline physical function might be explained by them engaging in a higher level of physical activity or having greater gains in muscle mass.
“The improvement in mobility could be due to testosterone-mediated increases in oxygen delivery and aerobic capacity or direct effects of testosterone on muscle function, mass, and strength, or both,” it said.
Improved mobility was associated with increased serum testosterone and haemoglobin concentrations from baseline, it noted.
“It is also possible that testosterone has effects on the brain that increase mobility by other mechanisms such as increased motivation to exercise or move.”
With testosterone also having been shown to benefits on improved energy and sexual function, this might justify treatment in older men with low levels, the authors suggested
“For an older man with an average serum testosterone concentration of less than 275 ng/mL (9.5 nmol/L), any combination of impaired mobility or stair climbing, self-reported sexual dysfunction, and unexplained anaemia or osteopenia might justify a trial of testosterone replacement therapy.
“For those older men without objective or subjective findings of persistent benefit after 1 year of therapy, testosterone therapy should be discontinued.”