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 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.