Prevalence of Iron Deficiency in Reproductive-Age Females on Anticoagulation for Venous Thromboembolism
Authors: Bakow Brianna R. , Zon Rebecca L. , Agarwal Shreya , Samuelson Bannow Bethany , Lim Ming Y , Parks Anna L. , Rajpurkar Madhvi , Rosovsky Rachel P. , Vankina Ritika , Yang Xin , Baumann Kreuziger Lisa 
Published: December 2024

Introduction
Heavy menstrual bleeding (HMB) occurs in up to 70% of reproductive-age females on anticoagulation. HMB can lead to iron deficiency with or without anemia, which can cause profound symptoms, affect organ function, and diminish quality of life. Despite these potential complications and strong associations between anticoagulation use, HMB, and iron deficiency with and without anemia, data on the prevalence of iron deficiency in reproductive-age females on anticoagulation is limited. This data could inform interventions to improve screening and appropriate treatment in this population.
Although there are multiple indications for anticoagulation, females of reproductive age are at particular risk for venous thromboembolism (VTE) in setting of estrogen exposures. This study, organized by the VENUS (Venous thromboembolism Network US) Women & Thrombosis committee, aimed to assess the prevalence of laboratory evaluation for and diagnosis of iron deficiency and anemia in reproductive-age females on anticoagulation for VTE.
Methods
We performed a retrospective, registry-based cohort study utilizing real-world electronic medical data from the TriNetX database from The Medical College of Wisconsin. Eligible patients included females ages 18-55 years old who were started on anticoagulation within 31 days after diagnosis of VTE based on ICD-10 codes. Our cohort was divided into individuals with and without laboratory testing of ferritin within 3 months of initiation of anticoagulation. Iron deficiency was defined as ferritin &lt; 50 ng/mL and anemia was defined as hemoglobin &lt; 12.0 g/dL.
Results
Our cohort included 5390 females with a median age of 35.1 years (8.9 SD) at the time of their VTE. Patient characteristics by race included White (59.7%), Black (32.5%), and 94.2% were not Hispanic. Only 25.8% (n=1390) had a ferritin checked within 3 months of anticoagulation initiation. Of those individuals, 41.7% (n=580) had ferritin levels ≤ 50 ng/mL and 30.9% (n = 430) had ferritin levels ≤ 30 ng/mL. The mean hemoglobin values were 11.2 g/dL (SD 2) in females with a ferritin ≤ 50 ng/mL and 11.1 g/dL (SD 2) in females with a ferritin ≤ 30 ng/mL.
Conclusions
We found that three-quarters of female patients prescribed anticoagulants did not undergo evaluation for iron deficiency. In the minority of patients who had a ferritin level checked within 3 months of initiation of anticoagulation, high rates of iron deficiency and anemia were identified. Our study highlights the lack of uniform testing for iron deficiency in this high-risk population and a huge gap in quality of care. Thus, the VENUS group recommends every reproductive-age individual with a uterus have a ferritin checked within 3 months of starting anticoagulation for VTE. Future studies will expand these analyses to the entire TriNetX cohort of 88 health care organizations to ensure generalizability and inform future interventions to improve outcomes.