Abstract 13215: Gender-affirming Hormones Are Associated With Increased Risk of QT Prolongation in Transgender Females

Abstract

Introduction: Women have a longer QT interval than men. This sex-specific difference is attributed to hormones associated with the biological female sex. Male-to-female transgender individuals often take antiandrogens such as spironolactone or goserelin in addition to estrogens to suppress testosterone effects while increasing feminine features. Effects of gender-affirming hormone therapy (GHT) on the QT interval in these individuals remains to be elucidated. Hypothesis: We assessed the hypothesis that the use of GHT is associated with an increased risk for QT interval prolongation in transgender females. Methods: We identified 46 transgender females through a search of the electronic medical records of a Veterans Administration hospital in Northern Nevada. Patients with a diagnosis of congenital long QT syndrome were excluded. Of these, 13 patients had ECGs before and after initiation of GHT and were included. We adapted the Tisdale score using the auto-calculated corrected QT interval (QTc) to estimate the risk of QT prolongation. Age, QTc, and Tisdale scores before and after GHT initiation were compared using the Wilcoxon signed-rank test. All tests were performed as two-tailed at a 5% level of significance. Results: All 13 study patients were taking estrogens. Of these, 3 (23.1%) were taking goserelin and 9 (69.2%) were taking spironolactone. Mean ± SEM age at ECG acquisition was 45.0 ± 4.4 and 47.7 ± 4.7 years before and after the initiation of GHT respectively. Mean ± SEM QTc after initiation of GHT was significantly higher compared to the baseline (467.5 ± 12.8 ms vs. 428.2 ± 7.1 ms) (Figure 1A). The average baseline Tisdale score was significantly smaller on follow-up (1-point vs. 3 points) (Figure 1B). Conclusions: GHT appears to be associated with increased QTc in transgender women. This needs to be interpreted with caution owing to the very small sample size in this study. Further studies to investigate the strength of this association, if it exists, are warranted.