From the article:
But this research also underscores the need for a long-term, prospective, randomized trial to truly understand whether testosterone therapy can be used without putting men at greater risk for cardiovascular events such as heart attacks, worsening of heart failure or sudden cardiac death.
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In the second study, researchers at Aurora Health Care, a large community-based health care system in Wisconsin, analyzed demographic and health data from 7,245 men with low testosterone levels from 2011-2014. After obtaining data from the electronic record systems of 15 hospitals and 150 clinics, the researchers looked at the combined cardiovascular event rate of heart attack, stroke and death in men with low testosterone who received testosterone therapy and in those who did not. They found the event rate at three years was low in both the treated group at 5.5 percent and in the untreated group at 6.7 percent, suggesting a potential cardiovascular benefit of testosterone replacement therapy on initial analysis. However, after adjusting for baseline differences including age, prior heart attack or stroke, cholesterol levels, smoking status and length of follow-up, researchers found no difference in cardiovascular event rates between the two groups.