Abstract
Background and Aims
Transferrin saturation (TSAT) is an indicator of iron deficiency or overload, but its relationship with mortality in patients with different stages of chronic kidney disease (CKD) is unclear. We investigated the association of TSAT with mortality in CKD patients.
Method
In 479 CKD patients (97 CKD3-4 patients, 298 CKD5 non-dialysis patients and 84 peritoneal dialysis patients; median age 58 years, 67% males, 33% cardiovascular disease, CVD, and 29% diabetes), biomarkers of iron status (plasma iron, TSAT, transferrin and ferritin), systemic inflammation (high sensitivity C-reactive protein, hsCRP, and interleukin-6, IL-6) and nutritional status were assessed. During median follow-up of 35.6 months, 139 (29%) patients died, and 176 (37%) patients underwent renal transplantation. Patients were stratified into low (n=157) and high (n=322) TSAT tertile groups. All-cause and CVD mortality risk were analyzed with competing risk regression with renal transplantation as competing risk.
Results
TSAT [median 23% (IQR 17-30%)] was negatively associated with presence of DM and CVD, body mass index, hsCRP, IL-6, Framingham´s CVD risk score (FRS), erythropoietin resistance index (ERI) and iron supplementation, and positively associated with hemoglobin, ferritin and s-albumin. In competing risk analysis, low tertile of TSAT was independently associated with increased all-cause mortality risk (sHR=1.50, 95%CI 1.05-2.14) after adjusting for CKD stages, 1-SD of FRS, 1-SD of hemoglobin, 1-SD of hsCRP, 1-SD of ESA dose and iron supplementation (Figure 1).
Conclusion
TSAT was inversely associated with mortality risk in CKD patients. When evaluating clinical outcomes of CKD patients, iron status using TSAT as a predictive marker, should be considered.
Predicting potential survival benefit of renal transplantation in patients with chronic kidney disease