title: Association between proton pump inhibitor use and anemia: a retrospective cohort study.
abstract: BACKGROUND
  Proton pump inhibitors (PPIs) are widely prescribed to treat gastrointestinal diseases. However, concerns have been raised regarding their long-term use. Gastric acid suppression may decrease iron absorption, and it remains uncertain whether iron-deficiency anemia may result from chronic PPI therapy.
  
  
  OBJECTIVE
  We aimed to explore the association between chronic PPI use and iron-deficiency anemia.
  
  
  METHODS
  We conducted a retrospective cohort study of adult patients in an academic outpatient setting who received PPI therapy for at least 1 year between January 1, 2004 and January 1, 2006. We compared the change in hematologic indices among patients receiving PPI therapy for at least 1 year with matched controls.
  
  
  RESULTS
  Of the 98 patients on chronic PPI therapy who met inclusion criteria, 35% had no documented indication for such therapy. At baseline, demographics and hematologic indices were similar between PPI-users and controls. Among patients on PPI therapy, all hematologic indices decreased from baseline, including hemoglobin (-0.19 g/dL, P=0.03), hematocrit (-0.63%, P=0.02), and mean corpuscular volume (-0.49 fL, P=0.05). PPI users had significant decreases in mean hemoglobin and hematocrit (P<0.01 for both) compared with matched controls. After adjustment for confounders, including rates of esophagogastroduodenoscopy, colonoscopy and remote cancer status, the odds ratio of decreasing hemoglobin by 1.0 g/dL while on chronic PPI therapy was 5.03 (95% CI, 1.71-14.78, P<0.01), while the odds ratio of decreasing hematocrit by 3% was 5.46 (95% CI, 1.67-17.85, P<0.01).
  
  
  CONCLUSIONS
  Among adult patients receiving chronic PPI therapy, there is a significant decrease in hematologic indices from baseline.
authors.affiliation: Department of Medicine, Michigan State University, B-301 Clinical Center, East Lansing, MI 48824, USA. erin.sarzynski@hc.msu.edu
authors.forename: Erin
authors.initials: E
authors.lastname: Sarzynski
authors.forename: Chethan
authors.initials: C
authors.lastname: Puttarajappa
authors.forename: Yan
authors.initials: Y
authors.lastname: Xie
authors.forename: Madhusudan
authors.initials: M
authors.lastname: Grover
authors.forename: Heather
authors.initials: H
authors.lastname: Laird-Fick
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018798:Anemia, Iron-Deficiency / Q000139:chemically induced*; D004909:Erythrocyte Indices / Q000187:drug effects; D005260:Female; D005744:Gastric Acid / Q000378:metabolism; D006400:Hematocrit; D006801:Humans; D008297:Male; D008875:Middle Aged; D054328:Proton Pump Inhibitors / Q000009:adverse effects* / Q000627:therapeutic use; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D054328:Proton Pump Inhibitors