Gastric Acid-Suppressive Drugs Raise Pneumonia Risk

A new study reaffirms that proton pump inhibitors (PPIs) are tied to a higher risk of community-acquired pneumonia (CAP), although the underlying mechanism remains unclear.

Researchers from St. Antonius Hospital (Nieuwegein, The Netherlands) conducted a population-based case-control study that included 430 cases with pneumonia and 1,720 matched controls. An elaborate diagnostic protocol was used to identify the causative microorganism of pneumonia. In the patient's recently starting PPI treatment, indications for treatment were assessed.

The researchers found that initiation of PPI therapy within the past 30 days was associated with about a three-fold increased risk of CAP; 12 of 430 patients with CAP had recently started a PPI (2.8%) versus 16 of 1,720 control subjects (0.9%). Oropharyngeal bacteria were evenly distributed among current, past and nonusers of PPIs. The researchers also noted that 4 of the 12 CAP patients (33%) who had recently started PPI treatment were admitted to the intensive care unit (ICU), compared with only 7% of nonusers. After adjusting for comorbidities, age, sex, and pneumonia severity score, recent PPI initiation was independently associated with ICU admission. Excluding patients who possibly were prescribed PPI treatment for early symptoms of pneumonia (protopathic bias) did not alter the study findings. The study was published early online on April 8, 2011, in the European Respiratory Journal.

"We hope that clinicians take home from this study that although PPI treatment is a very useful therapy, there are some risks in prescribing them,” said lead author Sabine Meijvis, MD, of the department of internal medicine. "We don't argue for less use of PPIs, but we think that only patients with the right indications for this treatment should use them.”

Prior studies have suggested that backflow and overgrowth of gastrointestinal bacteria during PPI therapy may result in colonization of the oral space and predispose to pneumonia. This effect is known to occur in mechanically ventilated patients, although it remains speculative in CAP.

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