It has been estimated that hypogonadism currently affects up to 4 million American men, and as the population ages, this number will only rise. Nevertheless, only 5% of these men are being treated actively for hypogonadism.1 According to the most recent United States census, 13% of the population is above the age of 65 and this is expected to increase by 16% by 2020.2
The Endocrine Society’s 2010 clinical practice guidelines3 outline a protocol for evaluating an adult male patient suspected of having androgen deficiency. In contrast to menopause, in which females experience all of the symptoms associated with the loss of estrogen within a well-defined period, men undergo a slow and gradual decline in their testosterone levels with a seemingly insidious onset of symptoms.3 For patients with a history and physical examination consistent with hypogonadism, the diagnosis can be “easily” confirmed by measuring serum testosterone levels, but how to interpret the results and decide who should be treated remains less clear.
Hypogonadism itself is broadly referred to as testicular failure associated with androgen deficiency,4 although such a broad definition encompasses many men and has required sub-classification based on cause and age.5 Late-onset hypogonadism (LOH) has been defined as a complex cluster of symptoms seen in aging men accompanied by a decrease in serum testosterone levels.6 Despite these definitions, the identification of these men is complicated and difficult.