Endocrine Abstracts

Objectives: Delayed puberty is very common in glucocorticoid treated boys with Duchenne Muscular Dystrophy (DMD) and is an additional threat to bone health. The current International Care Considerations for DMD recommend consideration of testosterone for treatment of hypogonadism from the age of 12 years, supported by recent studies that show that testosterone treatment in DMD improves bone density. Our objective was to investigate the current clinical practice amongst clinicians who manage testosterone treatment in DMD.

Methods: An online survey was circulated to paediatric clinicians involved in the management of puberty in DMD via patient groups in four countries (UK, USA, Italy, Israel).

Results: A total of 49/105 (47%) responses were received. 45% (22) of clinicians reported initiating testosterone therapy in boys with DMD with delayed puberty from 14 years, 35% (17) from 13 years and 35% (17) from 12 years. The majority of responders (47/49,96%) prescribe intramuscular therapy, 31% (15) topical, 2% (1) oral and 22% (11) reported other methods including subcutaneous testosterone. Regarding duration of therapy, 35% (17) of clinicians used a kick-start period of 4-6 months; 43% (21) prescribed continuous gradual build-up of therapy until either adult replacement dose was achieved, adult virilization was achieved (11,22%), testes were greater than 6-8mls (17,35%) or until LH levels were detectable (4,8%). 14% (7) continue testosterone indefinitely into adulthood. In those that discontinue therapy, testicular function was monitored upon discontinuation most commonly by reviewing testicular volume (31/48,65%), monitoring of morning (25/48,52%) or non-timed (12/48,25%) LH, FSH and testosterone levels or by GnRH stimulation testing (6/48,13%). Regarding thresholds for re-initiating testosterone in DMD upon discontinuation, there was a wide variation in cut-off levels reported and reliance on both non-timed and morning testosterone levels.

Conclusions: This international survey confirms initiation of testosterone in DMD in line with existing International Care Considerations at 12-14 years to address delayed puberty and as adjunctive therapy for bone health. However, there is wide variation in treatment strategies especially in relation to duration of therapy. Further guidance, particularly in regard to optimal regime, monitoring after therapy discontinuation and the need and threshold for re-initiating testosterone therapy is required.