Available online 12 August 2022

Transgender women in the United States are often prescribed spironolactone to lower serum testosterone concentrations. However, the safety of spironolactone on potassium concentrations is unknown

This retrospective study found in 44 transgender women taking spironolactone the prevalence of hyperkalemia to be extremely low.

There was no relation between the duration of spironolactone use and serum potassium concentrations.

Clinical relevance: Treatment guidelines for transgender women recommend suggest close monitoring of serum potassium concentrations in transgender women taking spironolactone. Unless patients have risk factors for hyperkalemia such as chronic kidney disease, the risk of hyperkalemia with spironolactone use is low and therefore frequent monitoring of potassium concentrations may be unnecessary.

To assess the incidence of hyperkalemia in transgender women using spironolactone retrospectively.

This was a retrospective chart review of transgender women who received gender-affirming hormone therapy that included spironolactone from the endocrinology clinic between January 1, 2000 and September 6, 2018. The 44 subjects that had paired potassium levels documented and were on spironolactone were included and analyzed. Study outcomes included incidence of hyperkalemia (serum potassium >5.0 mmol/L), the relationship between duration and degree of hyperkalemia and difference between potassium concentrations at the beginning of spironolactone treatment vs last potassium concentration.

The median age of the subjects was 36.5 years. The cohort was predominantly of non- Hispanic white (32/44). No potassium level was above 5.5 mmol/ L and all subjects had creatinine < 2 mg/dL. The median duration of treatment was 25 months (range 2- 92 months) and a total of 140 potassium measurements were available. The mean potassium concentration (3.87 mmol/L) before the initiation of spironolactone wwas lower than the mean potassium concentration (4.03 mmol/L) while on spironolactone and the difference was statistically significant but clinically insignificant (mean difference 0.16 mmol/L, p=0.013). The regression beta i.e., average change in potassium concentration per one additional month of treatment duration was -00.1, 95% CI [-00.4, 0.01], p=0.255 which signified no relation between treatment duration and spironolactone use.

No subject had laboratory evidence of hyperkalemia after the initiation of spironolactone. Frequent measurement of potassium levels might be unnecessary in transgender women taking spironolactone, in patients with serum creatinine < 2 mg/dL

Transgender

Spironolactone

Gender affirming care

© 2022 Published by Elsevier Inc. on behalf of the AACE.