Impact of Altitude on Anemia, Erythropoietin-Stimulating Agent, and İntravenous Iron Requirement in Hemodialysis Patients

INTRODUCTION: Anemia is an important cause of morbidity and mortality in chronic kidney disease (CKD). Previous studies have shown the curative effects of altitude on anemia in hemodialysis (HD) and non-hemodialysis CKD. This study examined the effect of altitude on erythropoietin stimulating agent (ESA), İntravenous (IV) iron requirement in HD patients.
METHODS: This retrospective observational study was conducted between January and June 2023. The study group was divided into two groups according to altitude: HD patients living in Van Province (1,730 meters, 5,765 feet) in the high-altitude group (HAG) and HD patients living in Istanbul Province (sea level) in the low-altitude group (LAG). In addition to hemoglobin (Hgb) and ferritin levels, ESA and IV iron doses were recorded at monthly visits for six months. These values of the HAG and LAG were compared.
RESULTS: A total of 184 patients were included in the study (HAG: 108 patients and LAG: 79 patients). HD patients living at high altitudes had statistically significantly higher Hgb and ferritin values compared to low altitudes (HAG: 1.5 g/dL, 749 pg/L vs. LAG: 11.3 g/dL; 543 pg/L; p=0.04, p< 0.001, respectively). In addition, ESA (HAG: 53 IU/kg/week, 12000 IU/month vs. LAG: 100.6 IU/kg/week, 24000 IU/month; p<0.001) and IV iron (HAG: 208.3±151 mg/month vs. LAG: 364.9±300.8 mg/month; p=0.002) dose was significantly lower.
DISCUSSION AND CONCLUSION: HD patients living at high altitude needed lower doses of ESA and IV iron to reach higher Hgb values than patients living at lower altitude.