Relative Contributions of Body Iron Status and Uremia Severity to Anemia in Patients with Advanced Chronic Renal Failure

Abstract

Anemia in chronic renal failure is predominantly caused by diminished erythropoietin synthesis by diseased kidneys. While iron deficiency is often stated as a cause of anemia in chronic renal failure prior to end-stage renal disease, its relative contribution is debated. It is speculated that rather than frank ‘iron deficiency’, many patients with chronic renal failure may indeed have impaired utilization of iron. We analyzed 139 consecutive patients with chronic renal failure starting maintenance hemodialysis to determine the relationship between hematocrit, measures of renal function (blood urea nitrogen and serum creatinine concentration), and measures of iron availability (serum transferrin saturation, serum iron level and serum ferritin). The 139 study subjects (60 men, 79 women) comprised 116 blacks (83%), 15 hispanics (11%), and 8 whites (6%) of a mean age 56 ± 15 years. Only 23 (17%) of 139 subjects had positive hemoccult stool test for blood. Their mean hematocrit was 24 ± 4.5%, mean blood urea nitrogen concentration was 121 ± 38, mean serum creatinine concentration was 12.6 ± 5.2 mg/dl, mean serum transferrin saturation was 22 ± 14%, mean serum ferritin level was 235 ± 194 U/l, mean serum iron level was 55 ± 40 U/l, and mean total iron binding capacity was 254 ± 93%. Multiple regression analysis with hematocrit as the outcome variable, and blood urea nitrogen level, serum creatinine concentration, serum albumin concentration, serum transferrin saturation, and serum ferritin level as the independent variables, showed an inverse correlation between hematocrit and serum creatinine concentration (p = 0.002). We conclude that in patients with chronic renal failure starting uremia therapy, anemia does not correlate with any of the commonly measured indices of body iron stores. We infer that impaired utilization of iron may be a significant factor in the anemia of chronic renal failure.

Parenteral Iron: Pharmacology and Clinical Use

“…Concomitant iron deficiency, resulting perhaps from a combination of inadequate intake and blood loss (gastrointestinal and during hemodialysis), is often cited as a cause of anemia in patients with chronic renal failure [24, 25, 26, 27, 28]. However, the magnitude or extent of gastrointestinal bleeding in patients with chronic renal failure has not been well quantified [24, 25, 26, 27, 28]. In fact, in several studies the incidence of positive Hemoccult stool tests in asymptomatic patients undergoing dialysis was less than 20% [26, 27, 28].…”

“…However, the magnitude or extent of gastrointestinal bleeding in patients with chronic renal failure has not been well quantified [24, 25, 26, 27, 28]. In fact, in several studies the incidence of positive Hemoccult stool tests in asymptomatic patients undergoing dialysis was less than 20% [26, 27, 28]. …”

Albumin-normalized serum zinc: a clinically useful parameter for detecting taste impairment in patients undergoing dialysis

“…In these cases, the diseased kidney has a diminished capacity not only to remove organic solutes from the body but also to monitor subtle changes in the concentration of inorganic compounds that may cause functional or biochemical disturbances [3,4].…”

The epidemiology and control of anaemia among pre‐ESRD patients with chronic kidney disease

“…An important observation of this NHANES III analysis was that a substantial proportion of individuals with CKD were also iron‐deficient, as judged by the National Kidney Foundation‐Kidney/Dialysis Outcomes Quality Initiative (NKF‐K/DOQI) transferrin saturation and serum ferritin targets [31]. For example, among individuals with a CrCl between 20 and 30 mL min −1 , 46% of women and 19% of men had transferrin saturation < 20%, and 47% of women and 44% of men had a serum ferritin < 100 ng mL −1 [32]. Similar observations of iron deficiency in individuals with CKD have been reported for other clinical populations [32–34].…”