Medical Student Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ Norwood, United States
Background: Intravenous (IV) iron is an alternative to poorly tolerated oral iron formulations for iron deficiency, and is the preferred route of administration for end-stage renal disease (ESRD) patients on dialysis. New IV iron formulations have been marketed in recent years, but resultant changes in utilization patterns are not well described.
Objectives: To assess temporal trends in the use of available IV iron formulations among Medicare beneficiaries with and without ESRD
Methods: We conducted a retrospective cohort study using a 20% sample from Medicare claims data (1/1/2008 - 12/31/2019, ~10 million beneficiaries per year). We identified older subjects (age >65) and ESRD patients on dialysis (any age) in the data and assessed IV iron initiation of iron dextran, ferric gluconate, iron sucrose, ferumoxytol, or ferric carboxymaltose in each group. We described trends in the rate of initiating different IV formulations over time and characteristics of initiators of each formulation, including demographics, comorbidities such as gastrointestinal conditions, and medication use.
Results: Among 420,234 non-dialysis patients initiating IV iron (mean age 74, 80% white, 66% female, 51% cancer, 33% heart failure), the rate of use of older formulations decreased from 2008 to 2019: iron sucrose (49% to 26%), ferric gluconate (17% to 5%), and iron dextran (31% to 5%). Correspondingly, the rate of use of newer formulations that entered the market during the study period, ferric carboxymaltose and ferumoxytol, rose to 39% and 25% in 2019, respectively. By 2019, ferric carboxymaltose was the most initiated IV iron formulation among non-dialysis patients. Among 173,434 ESRD patients on dialysis initiating IV iron (mean age 68, 54% white, 47% female, 29% cancer, 64% heart failure), ferric carboxymaltose and ferumoxytol had an average rate of use of <1% each and did not significantly penetrate the market. The use of older formulations remained largely consistent from 2008 to 2019, with iron sucrose continuing to dominate the market (77% to 91%) and ferric gluconate use, a second option after iron sucrose, declining (21% to 8%). All p-values for trends were <0.05.
Conclusions: As new IV iron formulations (ferric carboxymaltose and ferumoxytol) entered the market between 2008 and 2019, their usage among non-dialysis patients quickly increased, becoming the preferred options over most older formulations. However, among ESRD patients on dialysis, iron sucrose remained the primary formulation initiated. Since all five formulations are effective at treating iron deficiency, future studies may examine the various drivers of these differences in formulation choice, including cost, convenience, indications, and provider preference.
