Gastric acid-suppressive medications may increase risk of developing pneumonia

Individuals who use gastric acid-suppressive medications may be at an elevated risk of developing community-acquired pneumonia, according to an article in the October 27 issue of JAMA.

According to background information in the article, 20 to 40 percent of the general population experiences at least one episode of indigestion or gastroesophageal reflux disease (GERD, a backflow of acid from the stomach into the swallowing tube or esophagus) and five percent consult a general practitioner for their ailment. In primary care, a common way to treat these symptoms is to reduce gastric (stomach) acid secretions with the use of acid-suppressive drugs. However, these medications can increase vulnerability to infections, as stomach acidity is a major defense mechanism against ingested pathogens.

Robert J.F. Laheij, Ph.D., from the University Medical Center St. Radboud, Nijmegen, Netherlands, and colleagues studied pneumonia rates of both patients who did and did not use acid-suppressing medication. Patients were identified from the Integrated Primary Care Information (IPCI) database between January 1995 and December 2002. The study population included 364,683 individuals from the Netherlands who developed 5,551 cases of pneumonia for the first time.

The researchers found that current use of all acid-suppressive drugs was associated with a 27 percent increase in the risk of pneumonia, with higher risks for specific classes of acid-suppressive drugs (such as proton pump inhibitors or H2-receptor antagonist drugs).

"The effectiveness of acid-suppressive drugs in the treatment of upper gastrointestinal tract symptoms is excellent. Acid-suppressive drugs nevertheless seem to have some significant drawbacks," write the authors. "Persons using acid-suppressive drugs more often develop a community-acquired pneumonia compared with those who do not use acid-suppressive drugs, which is in general not a problem because the risk for developing pneumonia is low. The increased risk for pneumonia is a problem for patients who are at increased risk for infection, especially because community-acquired pneumonia is potentially dangerous."

In an accompanying editorial, James C. Gregor, M.D., from the University of Western Ontario, London, Ontario, Canada, examines the effectiveness and risks of acid-suppressive drugs.

"Because of their efficacy and impressive safety profile that has far exceeded original expectations, acid-suppressing drugs have consistently been among the most widely prescribed medications worldwide, with almost $13 billion in sales in 1998 and an annual growth rate of three percent."

Dr. Gregor states that these drugs are now widely used to treat a number of gastrointestinal diseases. "As the indications for these drugs expand further and as the population ages, the number of patient-years of exposure will continue to increase and any unrecognized complications will become of greater importance."

He concludes by saying: "If acid suppression causes some cases of pneumonia, it is reassuring that the risk is relatively small and that the complication in most cases is usually amenable to therapy. However, no medication is without potential adverse effects. Concerns for patient safety should guide initial prescribing and perhaps more importantly, chronic use of even the most apparently benign drug."