AN ANALYSIS OF TESTOSTERONE IMPLANTS FOR ANDROGEN REPLACEMENT THERAPY

OBJECTIVE To review 13 years of experience using fused crystalline tes tosterone implants for androgen replacement therapy in order to identi fy pattern of usage (including continuation rates) and adverse events emerging during therapy and factors associated with adverse events inc luding implant extrusions. DESIGN Retrospective review of prospectivel y collected data on characteristics of patients and implant procedures performed as well as adverse events reported during routine follow-up , PATIENTS Over 13 years 973 implant procedures using fused crystallin e testosterone implants were performed in 221 men. MEASUREMENTS Contin uation rates and adverse events such as extrusions, bleeding, infectio n or others were recorded and analysed in relationship to characterist ics of the patient and the implant procedure performed. RESULTS Overal l rate of adverse events (108/973, 11.1%) was significantly related to increased numbers of implants (4.2 +/- 0.1 vs 4.0 +/- 0.03, P = 0.031 ) and higher levels of physical activity at work (P = 0.030). The most common adverse effect was extrusion (83/973, 8.5%) which was related to occupational classification (P = 0.033) and increasing work activit y (P = 0.044) and occurred more frequently than by chance in multiple (16 vs 3.3 expected) rather than single (65 vs 76.1 expected) episodes . Bleeding (22/ 973, 2.3%) was significantly associated with an increa sed number of implants (4.5 +/- 0.2 vs 4.0 +/- 0.03, P = 0.020) but ev en in the worst cases (3/22) it was of minor clinical importance. Infe ction was rare (6/973, 0.6%) but occurred more among thinner men. The overall continuation rate was 92.7% increasing from 86% after the firs t implantation to >99% after the tenth implant. CONCLUSIONS This study demonstrates the very satisfactory clinical acceptability of testoste rone pellet implants for androgen replacement therapy within a single unit with experienced operators. The only regular adverse effect is ex trusion, which may be related to mechanical factors such as habitual w ork activity but also possibly procedural factors. Other adverse effec ts such as bleeding, infection and fibrosis were rare, An improved met hod of implant delivery would enhance this old but durable technology.