Epidemiology of anemia in patients with stages 3-5D chronic kidney disease: a cross-sectional study in Harbin, Northeast China

Objective To determine the prevalence of anemia in subjects with chronic kidney disease (CKD)3-5, reveal the characteristics of anemia in those patients, and provide data for promoting this situation.Methods This was an epidemiological, cross-sectional, single-center study under routine clinical practice conditions. Data of 859 CKD 3-5 patients admitted to the First Affiliated Hospital of Harbin Medical University or in its hemodialysis center from October 2011 to August 2015 were used to understand the prevalence of anemia in those patients (stage 3: n=241; stage 4: n=195; stage 5: n=243; stage 5D: n=180).Results The mean hemoglobin (Hb) value for patients with CKD 3 was 119.0±23.2 g/L, compared to 102.3±20.4 g/L in patients with CKD 4, to 86.1±19.3 g/L with CKD 5ND (CKD 5 not on dialysis), and to 101.6±18.2 g/L with CKD 5D (CKD 5 on dialysis). There was statistically significant difference among the groups (F=103.48, P<0.01). The overall prevalence of anemia was 43.2%, 71.3%, 95.9%, and 78.9% in patients with CKD 3, CKD 4, CKD 5ND and CKD 5HD, respectively. The prevalence of moderate anemia 90 g/L≤Hb<120 g/L (male)/110 g/L (female) was 83.7% (CKD 3), 61.9% (CKD 4), 51.1% (CKD 5), and 71.1% (CKD 5D) respectively. According to the standard of anemia in China, the patients with normocytic anemia accounted for 66.7%. The linear regression showed that Hb (g/L)=79.80+0.91×eGFR mL·min^-1·(1.73 m²)^-1 (R=0.59, F=57.73, P<0.01).Conclusions We found that the prevalence of anemia was increased with the raised prevalence of CKD 3-5. Normocytic and normochromic anemia is the most common form in patients with CKD 3-5D, in accordance with its pathogeneses. In patients with CKD 3-5, mean Hb level was decreased as eGFR was linearly decreased.