Iron deficiency resolution and time to resolution in an American health system.

Iron deficiency (ID) is a global health problem with consequences independent of anemia, including impaired cognition and exercise tolerance. The time from laboratory diagnosis to resolution of ID has not been defined. In a retrospective review of electronic medical record data from a Minnesota statewide health system, we identified patients with ID (ferritin level < 25 ng/mL). Patients with at least one follow-up ferritin level within 3 years were included. Patients with a subsequent ferritin > 50 ng/mL were classified as having resolved ID. Descriptive statistics and time-to-event analyses were used to determine proportion of ID resolution and time to resolution, and to evaluate characteristics predictive of resolution. We identified 13,084 patients with ID between 2010 to 2020. We found that 5,485 (41.9%) had resolution within 3 years of diagnosis, while 7,599 (58.1%) had no documented resolution. The median time to resolution was 1.9 years (IQR 0.8, 3.9 years). Factors associated with greater likelihood of resolution included age 60 years and older (aHR 1.56 [95% CI 1.44 - 1.69]), male sex (1.58 [95% CI 1.48 - 1.70]) and treatment with intravenous iron (2.96 [95% CI 2.66 - 3.30]). Black race was associated with a lower likelihood of resolution (0.73 [95% CI 0.66 - 0.80]). We observed a high proportion of persistent ID and prolonged time to resolution overall, with greater risk of lack of resolution among females and black individuals. Targeted knowledge translation interventions are required to facilitate prompt diagnosis and definitive treatment of this prevalent and correctable condition.