The study was based on data collected from administrative claims from a commercially insured and Medicare population in the USA and GP records from the UK. A total of 544,115 received first prescriptions of testosterone supplementation (37.4%injection, 6.9%patch, and 55.8% gel). Compared with men using gels, injection initiators had higher hazards of cardiovascular events (MI, unstable angina, and stroke) (HR 1.26; 95% CI 1.18-1.35), hospitalisation (1.16; 1.13-1.19), and death (1.34; 1.15-1.56) but not VTE (0.92; 0.76-1.11). There was no difference in risk between patients receiving gels and patches.
The study did not assess the safety of testosterone among users compared with nonusers of the drug.
The US FDA had recently issued a Drug Alert advising that manufacturers should change labelling to clarify the approved uses of these medications, and to add information about a possible increased risk of heart attacks and strokes in patients taking testosterone.