Rate of resolution of ID and time to resolution. Of 13 084 patients in the final study cohort, 5485 (42%) had documented ID resolution within 3 years of their initial diagnostic ferritin level. The median time to resolution among these patients was 1.9 years (IQR, 0.8-3.9). There were 7599 patients (58%) who did not have documented resolution within 3 years (eg, at least 1 additional ferritin level of <50 ng/mL).