Bajaj, J. S. et al. Association of proton pump inhibitor therapy with spontaneous bacterial peritonitis in cirrhotic patients with ascites. Am. J. Gastroenterol. 104, 1130–1134 (2009).

Credit: © HAAP Media Ltd, a subsidiary of Jupiterimages

PPI therapy is associated with spontaneous bacterial peritonitis in patients with advanced cirrhosis, report Jasmohan Bajaj et al. in their new study. Spontaneous bacterial peritonitis is associated with high morbidity and mortality, and is a frequent complication of cirrhosis as this liver disease can facilitate bacterial overgrowth. PPIs are commonly prescribed to patients with cirrhosis for many indications. By suppressing gastric acid production, these drugs also increase the likelihood of bacterial overgrowth.

In this retrospective, case–control study, 70 cirrhotic patients with paracentesis-proven spontaneous bacterial peritonitis were each matched to a comparable cirrhotic patient with ascites but no spontaneous bacterial peritonitis. PPI use was recorded. “Matching the two groups with respect to both age and Child–Turcotte–Pugh class [used to assess the prognosis of cirrhosis] is the crux of our study, because it is possible that a high Child score might overwhelm any potential effect of PPIs,” explains Bajaj.

69% of the patients with spontaneous bacterial peritonitis were taking a PPI before admission to hospital, compared with only 31% of those without spontaneous bacterial peritonitis. In addition, 47% of cirrhotic patients were using a PPI without a documented indication. “The increasing use of PPIs for non-approved indications has been worrying, especially in patients with cirrhosis who have deficient immunity,” comments Bajaj.

The strong association between PPI use and spontaneous bacterial peritonitis suggests a causal relationship, but proving one exists would require a prospective study. “We are planning a prospective study in which patients on PPIs for non-approved indications will be included for specific outcomes. We are also planning multicenter studies,” comments Bajaj on their future research.