Association Between Proton Pump Inhibitor Use and Anemia: A Retrospective Cohort Study

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. Aims 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 by3% 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.