Chevy Chase, MD--Although testosterone use has sharply increased among older men in the past decade, many patients appear to have normal testosterone levels and do not meet the clinical guidelines for treatment, according to new research accepted for publication in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism.
Testosterone is a key male sex hormone involved in maintaining sex drive, sperm production and bone health. Since testosterone levels tend to naturally decline as men age, lower levels of the hormone do not necessarily mean that an individual has hypogonadism, a condition that results from low testosterone. As the population ages and an increasing number of men struggle with obesity and diabetes, more men may experience low testosterone levels without meeting diagnostic criteria or displaying symptoms of hypogonadism.
"Over the past decade, older and middle-aged men are increasingly being tested for low testosterone levels and being prescribed testosterone medications, particularly in the United States," said one of the study's authors, J. Bradley Layton, PhD, of the University of North Carolina at Chapel Hill. "While direct-to-consumer advertising and the availability of convenient topical gels may be driving more men to seek treatment, our study suggests that many of those who start taking testosterone may not have a clear medical indication to do so."
To study testosterone trends, the retrospective incident user cohort study analyzed commercial and Medicare insurance claims from the United States and general practitioner health-care records from the United Kingdom during the period between 2000 and 2011. The study identified 410,019 American men and 6,858 U.K. men who began taking testosterone during this period. The analysis also found more than 1.1 million U.S. men and 66,000 U.K. men who had their testosterone levels tested during this time.
Since 2000, the number of men beginning testosterone therapy has almost quadrupled in the United States while only increasing by a third in the United Kingdom. The majority of these patients had not had their testosterone levels measured recently or only had them tested once prior to beginning treatment.
The Endocrine Society's Clinical Practice Guidelines on testosterone therapy in adult men recommend making a clinical diagnosis of androgen deficiency, or low testosterone, only in men with consistent symptoms and unequivocally low testosterone levels.
While testosterone testing has increased substantially in the United States and the United Kingdom, the study found the testing appeared to be more targeted in the United Kingdom. Many of the tests there identified men who did have reduced levels of the hormone.
"In the United States, we saw a clear trend where more and more men being tested actually had normal testosterone levels and non-specific symptoms," Layton said. "This is cause for concern as research examines potential risks associated with testosterone use."
Other authors of the study include: D. Li, J. Sharpless, T. Stürmer and M.A. Brookhart of the University of North Carolina at Chapel Hill; S.S. Jick of Boston University; and C.R. Meier of the University of Basel in Basel, Switzerland.
The study was funded by the National Institute of Health's National Institute on Aging.
The study, "Testosterone Lab Testing and Initiation in the United Kingdom and the United States, 2000-2011," was published online, ahead of print.
Founded in 1916, the Endocrine Society is the world's oldest, largest and most active organization devoted to research on hormones and the clinical practice of endocrinology. Today, the Endocrine Society's membership consists of over 17,000 scientists, physicians, educators, nurses and students in more than 100 countries. Society members represent all basic, applied and clinical interests in endocrinology. The Endocrine Society is based in Chevy Chase, Maryland. To learn more about the Society and the field of endocrinology, visit our site at http://www.