Hemoglobin discriminates stages of chronic kidney disease in elderly patients.

The prevalence of chronic kidney disease (CKD) increases with age, and anemia is known to affect the outcome of subjects with CKD. However, little is known with regard to the associations between metabolic complications and stages of CKD among elderly patients. Thus, the aim of the present study was to investigate the prevalence of CKD in elderly Chinese patients, as well as the associations between stages of CKD and clinically important complications of anemia. In total, 2,258 individuals with CKD, divided into younger (n=989) and elderly (n=1,269) groups, were enrolled in the study between June 2009 and December 2011. The glomerular filtration rate (GFR) was assessed using a 99mTc-DTPA renal dynamic imaging method (modified Gate's method). The levels of serum creatinine (SCr) and hemoglobin (Hb), and the hematocrit (HCT) were measured simultaneously per manufacturer's instructions. In the elderly group, the levels of SCr and proportional ratios were higher, while the GFR, Hb level, HCT and proportional ratios were lower when compared with the values in the younger group. Statistically significant differences were observed in the Hb concentrations when comparing individuals classified with different stages of CKD in the younger and elderly groups. In the younger group, there was no significant difference in the Hb concentrations between the stage 3a and 3b CKD patients. However, in the elderly group, the Hb concentrations were significantly higher in patients classified with stage 3a CKD when compared with those with stage 3b, whose GFR cutoff point was <60 ml/min/1.73 m2. In conclusion, the results indicated that Hb levels may be used to discriminate stages of CKD in elderly patients; thus, Hb may be used as a biomarker to assess the severity of CKD.