Kidney Week

Abstract: TH-PO877

Associations of Anemia and Iron Parameters with Fatigue in Persons with and without Kidney Diseases

Session Information

• Anemia and Iron Metabolism
  October 24, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Anemia and Iron Metabolism

• 200 Anemia and Iron Metabolism

Authors

• Gregg, Lucile Parker, Baylor College of Medicine, Houston, Texas, United States

Lucile Parker Gregg, MD, MS, FASN

• Vu, Christine, Texas Tech University Health Sciences Center, Dallas, Texas, United States

Christine Vu, MPH

• Perkins, Aaron Rode, Texas Tech University Health Sciences Center, Dallas, Texas, United States

Aaron Rode Perkins, MS

• Yang, Hui, Texas Tech University Health Sciences Center, Dallas, Texas, United States

Hui Yang, MS

• Navaneethan, Sankar D., Baylor College of Medicine, Houston, Texas, United States

Sankar D. Navaneethan, MD, MS, MPH, FASN

• Alvarez, Carlos A., Texas Tech University Health Sciences Center, Dallas, Texas, United States

Carlos A. Alvarez, PharmD, MS

Background

Low estimated glomerular filtration rate (eGFR) is associated with anemia and absolute and functional iron deficiency. Hemoglobin and biomarkers of iron stores are associated with fatigue, but it is unclear if an eGFR <60 mL/min/1.73 m² modifies these relationships.

Methods

Using data from the National Institutes of Health All of Us cohort, we identified individuals who answered the self-reported fatigue item over the last 7 days at cohort enrollment, with fatigue defined as any fatigue (i.e., mild, moderate, severe, or very severe) vs. none. We limited the sample to individuals who had a hemoglobin, ferritin, and/or transferrin saturation (TSAT) level within 1 year of cohort enrollment. Ferritin <30 ng/mL (consistent with KDIGO guidelines) or TSAT <20% identified patients with likely absolute iron deficiency. Multivariable logistic regression evaluated the associations of hemoglobin, ferritin, and TSAT levels with fatigue, adjusting for age, sex, race, and ethnicity, with multiplicative interaction terms to assess if an eGFR <60 mL/min/1.73 m² modified these associations.

Results

Of 19,310 individuals included in the cohort, fatigue was present in 16,587 (86%). Compared to those without fatigue, patients with fatigue had lower median (IQR) hemoglobin, 10.5 (8.8, 12.2) vs. 10.7 (8.8, 12.6) g/dL, P<.0001, and lower TSAT, 21 (13, 30) vs. 23 (15, 32), P<.0001 (Figure A). Those with fatigue were also more likely to have hemoglobin <10 g/dL (40% vs. 31%, P<.0001), ferritin <30 ng/mL (32% vs. 29%, P=.003), and TSAT <20% (56% vs. 48%, P<.0001). Fatigue was present in 7,164 (85%) of those with an eGFR ≥60 and 5,243 (86%) with an eGFR <60 mL/min/1.73 m². Hemoglobin <10 g/dL was associated with higher odds of fatigue in those with an eGFR <60 but not in those with an eGFR ≥60 mL/min/1.73 m², interaction P<.0001 (Figure B).

Conclusion

Hemoglobin <10 g/dL was associated with fatigue in those with an eGFR<60 but not ≥60 mL/min/1.73 m², possibly related to differences in the physiology of oxygen delivery and utilization in kidney disease. The presence of kidney disease limits the use of ferritin and TSAT levels to identify iron deficiency and may affect these associations.

Funding

• Veterans Affairs Support