A recent study published in 2013 warned that the risk of cardiovascular events is increased in men who have been prescribed testosterone therapy. Such cardiovascular events included heart attacks, congestive heart failures, coronary artery diseases, arrhythmias, and other cardiovascular disorders.
In particular, this robust systematic review found the risk was increased by 54% for cardiovascular events in general and by 61% for serious cardiovascular events (such as heart attacks).
Importantly, the investigation observed a significant discrepancy in the risk reported in trials funded by the pharmaceutical industry as compared to trials not funded by the industry. While the non-industry funded studies reported an overall increase in the risk of 106%, the industry funded ones actually reported an overall decrease in the risk by 11%.