Introduction: Testosterone replacement therapy (TRT) has been shown to be beneficial for men with hypogonadism. However, it is unknown how well hypogonadal men respond to TRT based on the severity of testosterone deficiency.
Aim: To determine subjective sexual response rates to TRT based on initial serum testosterone values, with particular interest in men with "low-normal" levels of total testosterone (TT).
Main outcome measures: Subjective responses to TRT in the domains of erectile dysfunction, libido, orgasm, and morning erections.
Methods: A retrospective study was performed of 211 men with sexual symptoms of hypogonadism who underwent TRT. All men had either low values of TT (<300 ng/dL) or free testosterone (FT) (<1.5 ng/dL). The cohort was divided into three groups based on initial TT levels: Group 1: 0-200 ng/dL (N = 26; 12.3%); Group 2: 201-300 ng/dL (N = 64; 30.3%); Group 3: 301 ng/dL or greater (N = 121; 57.3%). Improvement in erectile function was determined prior to addition of any other treatment (e.g., phosphodiesterase type 5 inhibitors). The mean follow-up was 9 months (range 3-36 months).
Results: The mean age was 55.2 years. Testosterone gel was used in approximately two-thirds of each group. Improvement in libido was reported in 61.5%, 96.6%, and 29.8% for Groups 1, 2, and 3, respectively (P < 0.001). Improvement in erectile function was noted in 46.2%, 45.3%, and 73.6% for Groups 1, 2, and 3, respectively (P < 0.001). At time of last follow-up, the percentage of men continuing with TRT was 73.1%, 57.8%, and 58.7% for Groups 1, 2, and 3, respectively (P = nonsignificant).
Conclusions: These preliminary data suggest that men with sexual symptoms of hypogonadism respond well to TRT across a wide range of initial TT values, including men with low-normal TT levels. These men may have low bioavailable levels of testosterone that are not reflected in TT values.