The Utility of Potassium Monitoring in Gender-Diverse Adolescents Taking Spironolactone

CONTEXT: Current guidelines recommend close monitoring of electrolytes in transgender patients using spironolactone given the risk of hyperkalemia from mineralocorticoid antagonism. In patients taking spironolactone for other conditions, the rate of hyperkalemia is low, and the utility of frequent monitoring has been questioned. OBJECTIVE: We hypothesized that the rate of hyperkalemia in gender-diverse adolescents taking spironolactone is low and, when present, clinically insignificant. DESIGN AND OUTCOMES: A retrospective chart review of adolescents seen in a specialty gender clinic at a tertiary care pediatric hospital over 10 years identified patients prescribed spironolactone for gender transition. Study outcomes were the incidence of hyperkalemia, defined as serum potassium concentration >5.0 mmol/L, and the relationship between potassium levels and spironolactone dose and duration. RESULTS: Records were reviewed for 85 subjects with a mean ± SD age of 16.6 ± 1.7 years. There were a total of 269 potassium measurements (80 prior to spironolactone initiation and 189 during spironolactone treatment). Six potassium measurements in five subjects were >5.0 mmol/L, indicating a rate of hyperkalemia of 2.2%. None of the subjects had symptoms of hyperkalemia, and all elevated measurements were normal when repeated. Only one subject discontinued spironolactone after an elevated potassium measurement. There was no relationship between hyperkalemia and spironolactone dose. Potassium measurements decreased with increasing treatment duration. CONCLUSIONS: Hyperkalemia in patients taking spironolactone for gender transition is rare and when present is transient and asymptomatic. In the absence of other medical comorbidities, routine electrolyte monitoring in this population may be unnecessary.