How do gender-affirming hormone (GAHT) regimens affect cardiac repolarization in transgender individuals? A prospective, single-center cohort study from France, published in the JAMA Network Open, evaluated 120 adults (mean age 29.7 years) receiving GAHT. The cohort included 64 transgender men treated with injectable testosterone and 56 transgender women treated with transdermal estradiol plus antiandrogens, mainly oral cyproterone acetate.

Over two years, electrocardiograms (ECG) assessed corrected QT interval (QTc), T-wave maximal amplitude (TAmp), and QT peak (QTp) alongside circulating sex hormone measurements. GAHT initiation prolonged QTc by a mean of 20 milliseconds in transgender women (n=15) and shortened QTc by a mean of 17 milliseconds in transgender men (n=18) compared with pre-GAHT values (both P<.001). Associations between QTc and total testosterone were inverse in both groups.

No participant exceeded a QTc of 480 milliseconds or a change greater than 60 milliseconds. Findings suggest GAHT restores the QTc sexual dimorphism seen in cisgender adults. Clinicians should consider QTc monitoring, particularly in patients on concurrent QT-prolonging drugs.

Key takeaway: 

GAHT induces sex-specific QTc changes in transgender adults, highlighting the need for ECG monitoring in those with additional arrhythmic risk factors.