SP552HB LEVELS AND DOSE OF IRON ASSOCIATED WITH ADVERSE EVENTS ARE DIFFERENT BETWEEN YOUNGER AND ELDERLY HEMODIALYSIS PATIENTS

Abstract

Introduction and Aims: In the past two decades, the number of prevalent elderly patients undergoing maintenance hemodialysis (MHD) has been increasing. Elderly MHD have more clinical problems than younger patients such as malnutrition, inflammation, arteriosclerosis, intradialytic hypotension, and low levels of activities of daily living. We recently demonstrated that high ferritin levels and a high dose of intravenous iron of MHD associated with high risk of death and/or adverse events in TRAP study (Kidney Int. 2014). We performed a secondary analysis of the patients enrolled in the TRAP study, in which we compared anemia related factors and the effect of anemia treatment on the adverse events between younger and elderly MHD. Methods: Study design was the prospective observational multicenter study for period of 3 years. In 1095 patients with MHD, we measured blood levels of Hb, ferritin, iron, total iron-binding capacity, albumin in levels every 3 months, and high sensitive C reactive protein (hsCRP), β2microglbulin (MG) and intact-parathyroid hormone (iPTH) levels every 6 months. We compared the relation of anemia, nutritional, inflammatory markers and adverse events between younger (<65 yo) and elderly (≥65 yo) MHD. The composite events were defined as cerebro-cardio vascular disease, infection, hospitalization, and death. A time dependent cox hazard model was applied to the evaluation of the association between several above factors and adverse event. Results: Compared with younger HD patients, serum level of albumin (3.6±0.3 vs. 3.9±0.4 g/dL) and body mass index (20.7±0.8 vs. 21.9±1.2kg/m2) were significantly (P<0.05) lower and hCRP (0.02±0.03 vs. 0.08±0.03 mg/dL) was significantly (p<0.05) higher in elderly MHD. In elderly MHD, Hb levels was significantly lower (10.4±0.03 vs. 10.8±0.08 g/dL, p =0.017), and ferritin levels (78.2±8.2 vs.56.2 ±9.2 ng/mL, p=0.009) and the index of ESA hypo-responsiveness 'ESA/Hb' (282±205 vs. 354±314, p=0.004) were significantly higher than those of younger MHD. There were no significant differences in TSAT levels and dose of iron between younger and elderly MHD. In the elderly MHD, the risk of composite events was significantly smaller in only the patients with 10-11g/dL (HR:0.67, P=0.035). On the other hand, in younger MHD, compared to the patients with Hb levels <10g/dL, the risk of composite events were significantly decreased in higher Hb levels (10-11g/dL (HR:0.47, p=0.025), 11-12g/dL (HR:0.31, p=0.005), and >;12g/dL (HR:0.12, p=0.042)). In the elderly MHD, there was no significant association between TSAT and adverse events. On the other hand, in younger MHD, compared with patients with TSAT levels <15%, the risk of adverse events was significantly (HR:0.3, P=0.026) decreased in the patients with TSAT levels of 20-30%. Both of younger and elderly MHD, higher ESA/Hb levels (≥400) was significantly associated with higher risk for adverse events (HR: 2.24, p=0.006, HR:1.90, p=0.002). Dose of iron was significantly associated with high risk of composite events in both younger (HR:1.2, p=0.018 in 36 month) and elderly (HR:1.2, p=0.024 in 12month) MHD. Conclusions: The elderly MHD might have the higher ESA hypo-responsiveness and iron storage due to chronic inflammation and malnutrition. It has a possibility that higher Hb level such as younger MHD is not needed for prevention of adverse events in elderly MHD. Further studies which related to adequate anemia management for elderly MHD are needed.