Patients with anemia may also be diagnosed with iron deficiency. Results of previous studies have suggested an association between iron deficiency and mortality in patients with chronic kidney disease, even without the presence of anemia. Functional iron deficiency appears to confer higher risks for adverse outcomes compared with absolute iron deficiency.
There are few data available on iron deficiency states and associated outcomes in dialysis, particularly in peritoneal dialysis.
Brianna Hartley, MD, and colleagues conducted a data analysis designed to characterize iron deficiency states and rates of all-cause mortality in incident peritoneal dialysis. Results were reported during a poster presentation at the American Society of Nephrology Kidney Week 2022 in a poster titled Iron Deficiency Is More Common in Incident Peritoneal Dialysis Patients Without Anemia.
The researchers utilized data from BRAZPD, an adult peritoneal dialysis cohort across 122 clinics in Brazil (2004-2011). Incident peritoneal dialysis patients who had one or more laboratory results for transferrin saturation (TSAT, ferritin, and hemoglobin during the baseline period (≥6 months after initiation of peritoneal dialysis).
Iron deficiency was defined as TSAT <20%. The prevalence of iron deficiency, patient characteristics, and crude mortality rates per 1000 patient years were defined by iron deficiency states: (1) functional iron deficiency (hemoglobin ≥10 g/dL, TSAT <20%, ferritin ≥200 ng/mL); (2) functional iron deficiency with anemia (hemoglobin <10 g/dL, TSAT <20%, ferritin ≥200 ng/mL); (3) absolute iron deficiency (hemoglobin ≥10 g/dL, TSAT <20%, ferritin <200 ng/mL); and (4) absolute iron deficiency with anemia (hemoglobin <10 g/dL, TSAT <20%, ferritin <200 ng/mL).
The cohort included 1365 incident peritoneal dialysis patients; mean age was 59.7 years, 46.4% were male, and 49.1% had diabetes. The prevalence of iron deficiency was 14.9% (n=203). The prevalence of iron deficiency states was 5.2% for functional iron deficiency, 1.5% for functional iron deficiency with anemia, 6.3% for absolute iron deficiency, and 1.8% for absolute iron deficiency with anemia.
The mortality rate was highest for functional iron deficiency at 195.6 deaths per 1000 patient years, compared with the other three iron deficiency states.
In summary, the researchers said, “In incident peritoneal dialysis, we found a 14.9% prevalence of iron deficiency; most patients had iron deficiency without anemia. This finding may be of importance given screening for iron deficiency is recommended with low hemoglobin. Anemic patients were infrequently iron deficient, which may suggest more active iron replacement triggered by low hemoglobin. Incident peritoneal dialysis patients with functional iron deficiency without anemia appeared to exhibit a higher all-cause mortality rate than other iron deficiency stages. Further studies are needed to confirm these findings.”
Source: Hartley B, Rigodon V, Larkin JW, et al. Iron deficiency is more common in incident peritoneal dialysis patients without anemia. TH-PO677. Abstract of a poster presented at the American Society of Nephrology Kidney Week 2022; November 3, 2022; Orlando, Florida.