Proton pump inhibitor therapy is a risk factor for Clostridium difficile‐associated diarrhoea

Summary Background Inhibition of gastric acid removes a defence against ingested bacteria and spores, increasing the risk of some forms of gastroenteritis. Previous studies investigating a possible link between acid suppression therapy and Clostridium difficile‐associated diarrhoea have reported conflicting results. Aim To investigate whether acid suppression therapy is associated with an increased risk of C. difficile‐associated diarrhoea. Methods Prospective case–control study of 155 consecutive in‐patients with C. difficile‐associated diarrhoea. Results Antibiotics had been received by 143 (92%) of the C. difficile‐associated diarrhoea group and 76 (50%) of the controls during the preceding 3 months. Among those receiving antibiotics, 59 (41%) of the C. difficile‐associated diarrhoea group had also received acid suppression, compared with 21 (28%) of controls (OR 1.84, CI 1.01, 3.36, χ2 = 4.0, P = 0.046). Among the entire C. difficile‐associated diarrhoea group 64 (41%) had received acid suppression compared with 40 (26%) of controls (OR 1.99, CI 1.19, 3.31, χ2 = 7.9, P = 0.005). Logistic regression analyses found that C. difficile‐associated diarrhoea was independently associated with: antibiotic use (OR 13.1, 95% CI: 6.6, 26.1); acid suppression therapy (OR 1.90, 95% CI: 1.10, 3.29); and female sex (OR 1.79, 95% CI: 1.06, 3.04). Conclusions The risk of C. difficile‐associated diarrhoea in hospitalized patients receiving antibiotics may be compounded by exposure to proton pump inhibitor therapy.