title: Low initial vitamin B12 levels in Helicobacter pylori--positive patients on chronic hemodialysis.
abstract: BACKGROUND
  Helicobacter pylori has been identified as a possible cause of vitamin B12 deficiency in the general population. We assessed any potential relationship between low cyanocobalamin serum levels and Helicobacter pylori status in hemodialysis patients and subsequently correlated these results with the existence of anemia (a common complication in hemodialysis patients), and macrocytosis.
  
  
  METHODS
  In 29 chronic hemodialysis patients, active H. pylori infection was diagnosed using two different methods regardless of digestive symptoms: by searching for bacterial antigens in stools and by the detection of urea breakdown through breath testing. If these results were non-coincident, gastroscopy was performed and antral biopsies obtained. Patients were subsequently divided into group A (H. pylori-positive, n = 8, 28%) and group B (H. pylori-negative, n = 21, 72%). The corresponding initial values of erythrocytic folic acid, vitamin B12 and homocysteine prior to the first hemodialysis session of each patient were retrospectively collected.
  
  
  RESULTS
  Vitamin B12 levels (normal 200- 900 pg/ml) were significantly lower in group A compared to group B (225.4 +/- 111.9 vs. 707.9 +/- 258.3 pg/ml, p < 0.011). In group A, 5 patients (63%) had vitamin B12 deficiency (154 +/- 24.6 pg/ml). Baseline hematocrits, erythrocyte folic acid and serum homocysteine levels were not different between the groups, but mean corpuscular volumes were significantly higher in group A compared to group B (109.7 +/-14.1 vs. 91.8 +/- 8.8 fl, p = 0.002).
  
  
  CONCLUSIONS
  H. pylori-positive chronic hemodialysis patients may present with lower vitamin B12 blood levels and macrocytosis. H. pylori infection should be suspected in this population when low or low-normal vitamin B12 levels or macrocytosis exist.
authors.affiliation: Nephrology Section, Hospital Británico de Buenos Aires, Argentina. htrimarchi@hotmail.com
authors.forename: H
authors.initials: H
authors.lastname: Trimarchi
authors.forename: M
authors.initials: M
authors.lastname: Forrester
authors.forename: J
authors.initials: J
authors.lastname: Schropp
authors.forename: H
authors.initials: H
authors.lastname: Pereyra
authors.forename: E A
authors.initials: EA
authors.lastname: Freixas
mesh_terms: D000748:Anemia, Macrocytic / Q000209:etiology; D005260:Female; D005492:Folic Acid / Q000097:blood; D016481:Helicobacter Infections / Q000097:blood / Q000150:complications* / Q000175:diagnosis; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006710:Homocysteine / Q000097:blood; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D006435:Renal Dialysis; D012189:Retrospective Studies; D014805:Vitamin B 12 / Q000097:blood*; D014806:Vitamin B 12 Deficiency / Q000209:etiology*
chemical_list: D006710:Homocysteine; D005492:Folic Acid; D014805:Vitamin B 12