Variable serum testosterone levels suggests different treatment thresholds for hypogonadal symptomatology

Abstract

OBJECTIVE: Hypogonadism is diagnosed by a combination of symptomatology and low serum testosterone. The current study assessed hypogonadal symptoms in men≥40 years of age using the Androgen deficiency in Aging Male (ADAM) questionnaire. DESIGN: Retrospective study. MATERIALS AND METHODS: We surveyed a sample of 360 men (160 hypogonadal patients with total T≤300ng/dL and 200 controls with total T>300ng/dL) not on testosterone therapy between the ages of 40 and 90 years old. Using the Androgen Deficiency in the Aging Male (ADAM) questionnaire, we collected data with regard to sexual, psychological, and physical health. T levels were measured in morning blood samples by radioimmunoassay. Men who were currently on testosterone supplementation therapy (TST) or had received TST in the one month previous to reporting the survey were excluded from the analysis. RESULTS: Of the 10 hypogonadal symptoms that are part of the ADAM questionnaire, the prevalence of 5 symptoms were significantly different (p<0.05) between men with serum testosterone levels of ≤ 300ng/dL and men with T >300ng/dL. These included one sexual symptom (decreased libido), one psychological symptom (lack of energy), and three physical symptoms (decreased strength and endurance, decreased ability to play sports, and falling asleep after dinner). A range of serum testosterone levels (320-375ng/dL), rather than a solitary testosterone level, was found to differentiate between the five, most significantly different symptoms. Specifically, serum testosterone thresholds of 375ng /dl were identified for decreased libido, 350ng/dL for lack of energy, 320ng/dL for decreased ability to play sports, 340ng/dL for decreased strength and endurance, and 360ng/dL for increasingly falling asleep after dinner. CONCLUSION: Among men >40 years of age presenting to a men's health clinic, symptoms of decreased libido, decreased energy, decreased strength and endurance, decreased ability to play sports, and falling asleep after dinner were most associated with low total serums testosterone. The threshold serum testosterone for these hypogonadal symptoms ranged from 320 - 375 ng/dL. As such, we propose that unique testosterone thresholds exist in which hypogonadal symptoms become increasingly prevalent below variable demarcation points. Rather than using solitary, predefined levels of serum testosterone (i.e. <300 ng/dL) as cut-points for treatment, we recommend using a sliding scale based on symptomatology.