A medicine commonly used to treat an enlarged prostate may also be linked to fewer serious problems after a major heart attack, according to research from the University of Gothenburg.
The finding comes from Swedish health records and adds to growing evidence that male sex hormones may influence how the heart responds to sudden injury. Researchers caution, however, that the study does not yet support using the prostate medicine as a heart attack treatment.
Men and women can experience heart attacks differently. Previous research has suggested that men may sometimes develop larger areas of heart muscle damage, and scientists have been investigating whether male sex hormones help explain part of that difference. Testosterone and related hormones can influence inflammation, which is the body’s natural response to injury.
Inflammation is useful because it helps the body respond to damaged tissue, but too much inflammation can make an injury worse. During a heart attack, a coronary artery becomes blocked and part of the heart muscle is deprived of oxygen-rich blood. The longer the blockage continues, the more heart tissue can be damaged.
For the most dangerous type of heart attack, called an ST-elevation myocardial infarction, doctors usually try to reopen the blocked artery as quickly as possible. A common treatment is balloon angioplasty, in which a thin tube is guided into the blocked artery and a small balloon is expanded to restore blood flow. A stent is often placed to help keep the artery open.
Restoring blood flow saves heart muscle and can be lifesaving, but the return of blood can also trigger a strong inflammatory response. Researchers are therefore interested in factors that may affect this response and determine how much lasting damage occurs. Male hormones are one possible part of this complicated process.
The University of Gothenburg team focused on finasteride, a medicine widely used for benign prostatic hyperplasia, or an enlarged prostate. This common condition becomes more frequent as men age and can cause problems such as difficulty urinating or needing to urinate often. Finasteride helps shrink the prostate by changing the way the body processes male hormones.
The drug blocks an enzyme that normally converts testosterone into dihydrotestosterone, often shortened to DHT. DHT has stronger effects than testosterone in some tissues and plays an important role in prostate growth. By reducing DHT, finasteride can gradually reduce prostate size and improve urinary symptoms.
The researchers used information from SWEDEHEART, a major Swedish registry that collects data on heart disease and heart treatments, together with national health records.
They identified men who had experienced a severe STEMI heart attack and were treated with balloon angioplasty. Men taking medicines that alter male hormone activity were compared with similar heart attack patients who were not using those drugs.
Among patients taking finasteride, 20.8% experienced one of the serious complications measured in the study. Among carefully matched patients who were not taking the medicine, the figure was 24.3%. The complications included cardiac arrest, dangerous problems with the heart’s electrical system, severely reduced pumping ability or death within 30 days.
The difference was consistent with the researchers’ idea that reducing the effects of certain male hormones might lessen some of the harmful response to a heart attack. However, the pattern was not seen in patients receiving hormone-related medicines for prostate cancer. That difference shows that the relationship between hormones, medicines and heart injury is unlikely to be simple.
Hannah Colldén, a pharmacist and researcher at the University of Gothenburg, said the findings contribute to research on how sex hormones may affect the heart during events such as heart attacks. She also stressed that the result has no direct effect on current patient treatment. Finasteride should therefore not be started, stopped or changed in response to this study without medical advice.
The research was published in JAMA Network Open. Because it was based on registry records rather than a clinical trial that randomly assigned people to finasteride, it can show an association but cannot prove that the medicine caused the lower complication rate. Even careful matching cannot remove every possible difference between people who take a drug and those who do not.
The study is nevertheless interesting because the size and direction of the difference fit earlier biological research suggesting that male hormones can affect inflammation after heart injury.
The absolute difference between the groups was modest, at about 3.5 percentage points, so the result should not be interpreted as finasteride preventing most complications. It is better viewed as a clue that deserves testing in studies specifically designed to answer whether changing hormone activity can protect the heart.
Future research will need to confirm the finding in other populations and determine which patients, if any, could benefit. Researchers will also need to understand why finasteride showed an association while hormone treatments used for prostate cancer did not.
If clinical trials eventually support the result, the work could open a new direction for limiting heart damage, but current evidence is not strong enough to change standard heart attack care.
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Source: University of Gothenburg.
