Identifying women 45 years and younger at elevated risk for endometrial hyperplasia or cancer.

Objective: To estimate the prevalence of, and identify risk factors associated with, endometrial hyperplasia and/or cancer (EH/EC) in patients ≤45 years old undergoing endometrial sampling for abnormal uterine bleeding (AUB).

Methods: We performed a retrospective cohort study of patients 18-45 years old with AUB who underwent endometrial sampling between 2016 and 2019 within a US-based multi-hospital system using billing code queries. We used multivariable Poisson regression to identify factors associated with EH/EC and calculated prevalence stratified by these factors. We estimated predicted probabilities within combinations of characteristics in order to examine the range of risk in this population.

Results: Among 3175 patients, median age was 39 years (interquartile range [IQR]:35-43) and BMI was 29.7 kg/m (IQR: 24.2-36.9). Thirty-nine percent were non-Hispanic White, 41% non-Hispanic Black, 9% Hispanic, and 11% Asian/Other/Unknown. BMI and polycystic ovarian syndrome (PCOS) were associated with higher EH/EC risk; non-Hispanic Black race was associated with lower risk. EH/EC prevalence ranged from 2% in BMI <25 to 16% in BMI ≥50 kg/m (p-trend <0.001). These prevalence estimates differed by race/ethnicity with the lowest estimates in non-Hispanic Black patients (0.5% BMI <25 vs. 9% BMI ≥50) and highest in Hispanic patients (1.5% BMI <25 vs. 33% BMI ≥50). Accounting for combinations of risk factors, predicted probabilities were highest - 34-36% - among patients with PCOS, diabetes, BMI ≥50, and Hispanic or Asian/Other/Unknown race/ethnicity.

Conclusions: When accounting for combinations of key risk factors, risk of EH/EC in patients ≤45 years old with AUB ranges widely; the more nuanced estimates of risk presented here could help inform clinical decision-making about endometrial sampling in this population.