ODP425 Potassium Level Trends in Trans Females Using Spironolactone: A Retrospective Chart Review

INTRODUCTION: Endocrine Society guidelines for the treatment of gender dysphoric individuals recommend close monitoring of serum electrolytes, particularly potassium in trans females using spironolactone every 3 months (first year) and annually afterwards (1) due to risk of hyperkalemia from mineralocorticoid antagonism (2). Unless patients have kidney disease, the risk of hyperkalemia with spironolactone use is low and therefore monitoring of potassium levels has been questioned. A study conducted in trans youth on spironolactone treatment showed asymptomatic hyperkalemia in 2.2% of study subjects but no clinically significant hyperkalemia (3). OBJECTIVES: We hypothesized that the incidence of hyperkalemia in trans females using spironolactone is low and therefore when present is clinically insignificant. METHODS: This was a retrospective chart review of trans females who received gender-affirming hormone therapy that included spironolactone from the endocrinology clinic between January 1, 2000 and September 6, 2018. Out of a cohort of 244 trans subjects, 77 trans females had serum potassium levels documented. 6 trans women only on estrogen and 21 trans women with only one potassium measurement were excluded. The remaining 50 subjects that had an initial and at least 1 follow-up potassium were included and analyzed. ​ Study outcomes included incidence of hyperkalemia (serum potassium >5.5 mmol/L), the relationship between duration and degree of hyperkalemia and difference between potassium levels at the beginning of spironolactone treatment vs last potassium level as of September 2018. RESULTS: The mean age of the subjects was 42.8 years (SD 14.39 years). The cohort was predominantly of Caucasian race (62.8%). All subjects had spironolactone doses in the range of 100- 400 mg/ day. No potassium level was above 5.5 mmol/ L and all subjects had creatinine < 2 mg/dL. The average duration of treatment was 25 months (range 2- 142 months) and total 140 post-spironolactone potassium levels were available. The mean pre-spironolactone potassium level (3.88 mmol/L) was lower than mean post spironolactone potassium level (3.98 mmol/L) but the difference was statistically and clinically insignificant (p=0.106, paired t-test). The mean of cumulative post spironolactone potassium levels (4.03mmol/L) was higher than the mean of baseline potassium levels (p=0.012, unpaired t-test) but clinically insignificant. CONCLUSION: No subjects had laboratory evidence of hyperkalemia in our cohort of patients. This implies that frequent measurement of potassium levels might be unnecessary in trans women taking spironolactone, in patients with no history of chronic kidney disease. REFERENCES: 1 Hembree, W.C., et al., Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab, 2017 2 Epstein, M. and D.A. Calhoun, Aldosterone blockers (mineralocorticoid receptor antagonism) and potassium-sparing diuretics. J Clin Hypertens (Greenwich), 2011 3 Millington, K., E. Liu, and Y.M. Chan, The Utility of Potassium Monitoring in Gender-Diverse Adolescents Taking Spironolactone. J Endocr Soc, 2019 Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.