Pharmacist decision-making in clinical calculations using binary sex variables for transgender patients

Transgender and gender-diverse (TGD) individuals may experience physiologic changes from gender-affirming hormone therapy (GAHT) that complicate clinical calculations with binary sex variables. Common tools such as the Cockcroft-Gault creatinine clearance (CrCl) equation and the American College of Cardiology/American Heart Association Atherosclerotic Cardiovascular Disease pooled cohort equations (ACC/AHA ASCVD PCE) require binary sex inputs; however, no national or international guidelines specify whether sex assigned at birth or gender identity should be used when completing these clinical calculations that have binary sex inputs.

To evaluate (1) pharmacists' practices and confidence in using sex assigned at birth versus gender identity when calculating CrCl with the Cockcroft-Gault equation and ASCVD risk with the ACC/AHA ASCVD PCE in TGD patients and (2) the effects of GAHT on these decisions.

This IRB-approved, cross-sectional survey of licensed pharmacists (October 2024-February 2025) assessed clinical decision-making in transfeminine and transmasculine patients with and without long-established GAHT, as well as confidence and prior training. Paired comparisons were analyzed using McNemar's test to test for the effects of GAHT on these decisions.

A total of 190 pharmacists completed the survey. Most respondents selected sex assigned at birth for calculating CrCl using the Cockcroft-Gault equation and ACC/AHA ASCVD PCE in patients not receiving GAHT (85.2-85.4%). In patients with long-established GAHT, there was a consistent and statistically significant shift away from using sex assigned at birth (p < 0.001) when compared to patients not on long-established GAHT. Confidence was low overall (median 1-2 [IQR 1-3]), and 90% reported no prior training. Training was associated with higher confidence (p < 0.05), but not with consistent decision-making.

Pharmacists demonstrate inconsistent approaches and low confidence in deciding binary sex inputs in clinical calculations for TGD patients. Decision-making shifts with long-established GAHT and training improves confidence.