Journal Article

Association between serum phosphate levels and anemia in non-dialysis patients with chronic kidney disease: a retrospective cross-sectional study from the Fuji City CKD Network

Yokoo, Takashi, Ohkido, Ichiro, Kato, Kazuhiko, Kasai, Kenji, Nakashima, Akio

2023

Overview

Background Patients with chronic kidney disease (CKD) present high mortality and morbidity rates despite the availability of various therapies. Although CKD-mineral and bone disorder (MBD) and renal anemia are important factors in patients with CKD, only few studies have analyzed the relationship between them. Therefore, this study aimed to evaluate the relationship between CKD-MBD and anemia in patients with CKD who did not receive erythropoiesis-stimulating agent or iron therapies. Methods This retrospective cross-sectional study included patients with CKD aged ≥ 20 years with estimated glomerular filtration rate (eGFR) categories G2a to G5 who were referred to the Fuji City General Hospital between April 2018 and July 2019. The exclusion criterion was ongoing treatment for CKD-MBD and/or anemia. Results The data of 300 patients with CKD were analyzed in this study. The median age of patients was 71 (range, 56.5–79) years. The median eGFR was 34 (range, 20–48) mL/min/1.73 m 2 , and the mean hemoglobin (Hb) level was 12.7 g/dL (standard deviation, 2.3), which decreased as the CKD stage increased. In a multivariate linear regression analysis of anemia-related factors, including age, renal function (eGFR), nutritional status, inflammation, and iron dynamics (serum iron level, total iron-binding capacity, ferritin levels), the serum phosphate levels were significantly associated with the Hb levels (coefficient [95% confidence interval], -0.73 [-1.1, -0.35]; P  < 0.001). Subgroup analysis revealed a robust association between serum phosphate levels and Hb levels in the low-ferritin (coefficient [95% confidence interval], -0.94 [-1.53, -0.35]; P  = 0.002) and advanced CKD groups (coefficient [95% confidence interval], -0.89 [-1.37, -0.41]; P  < 0.001). Conclusions We found an association between high serum phosphate levels and low Hb levels in patients with CKD not receiving treatment for anemia. These results underscore the possibility of a mechanistic overlap between CKD-MBD and anemia.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Anemia / Blood / Bone diseases / Chronic kidney disease / Chronic kidney disease-mineral and bone disorder / Chronic kidney failure / Complications and side effects / Creatinine / Cross-sectional studies / Diagnosis / Dialysis / Epidermal growth factor receptors / Erythropoiesis / Erythropoietin stimulating agent / Ferritin / Glomerular filtration rate / Health aspects / Hemodialysis / Hemoglobin / Inflammation / Internal Medicine / Iron / Iron therapy / Kidney diseases / Leukocytes / Medicine / Medicine & Public Health / Metabolism / Minerals / Morbidity / Multivariate analysis / Nephrology / Nutrition / Nutritional status / Patients / Phosphates / Proteins / Regression analysis / Renal function / Research Article / Risk factors / Sensitivity analysis / Serum phosphate / Variables