Acid Blockers Linked to Pneumonia Risk

Study Shows Hospital Patients Who Take Acid-Reducing Drugs May Be at Risk for Pneumonia

Medically Reviewed by Louise Chang, MD on May 26, 2009
From the WebMD Archives

May 26, 2009 -- An estimated 33,000 deaths a year from hospital-acquired pneumonia may result from the practice of routinely prescribing proton pump inhibitors and other acid-suppressing drugs during hospitalization to patients who don't need them.

Use of acid-reducing drugs was associated with a 30% increased risk for developing pneumonia in a newly reported study.

The drugs are typically given to reduce the risk of stress-related ulcers, which can be life threatening. But they are often prescribed to patients with a very low risk for developing the ulcers, says study researcher Shoshana J. Herzig, MD, of Beth Israel Deaconess Medical Center and Harvard School of Medicine.

Use of proton pump inhibitors (PPIs) has been associated with a slight increase in community-acquired pneumonia risk in several recent studies. But the new research is the first to explore a possible link in hospitalized patients who don't require a ventilator to breathe and are treated outside intensive care units (ICUs).

The study appears in the May 27 issue of TheJournal of the American Medical Association.

"In our study, the risk to the individual patient was small," Herzig tells WebMD. "But because so many people are hospitalized each year, the number of patients involved is not insignificant."

Hospital Patients and PPIs

Previous studies suggest that acid-suppressing medications are prescribed to between 40% and 70% of hospitalized patients in the U.S.

Herzig and colleagues reviewed the medical records of almost 64,000 non-ventilated, non-ICU adult patients hospitalized and treated at Beth Israel Deaconess between 2004 and 2007 and found that 52% were prescribed acid-reducing drugs.

Of these, 83% were prescribed proton pump inhibitors and 23% received another class of acid-suppressives known as H2 blockers. Examples of PPIs include Aciphex, Nexium, Prevacid, Prilosec, and Protonix. H2 blockers include Axid, Pepcid, Tagamet, and Zantac.

In nine out of 10 cases the drugs were prescribed within 48 hours of admission.

The review of patient records revealed that:

  • 3.5% of patients developed hospital-acquired pneumonia.
  • After adjusting for other risk factors for pneumonia, use of acid-suppression drugs was associated with a 30% increased risk for developing hospital-acquired pneumonia.
  • The association was statistically significant for proton pump inhibitors, but not for H2 blockers.

Some 40 million patients are discharged from the hospital in the U.S. each year, and roughly one in five patients who develop hospital-acquired pneumonia die as a result.

Assuming that 50% of hospitalized patients are prescribed acid-suppressing drugs, Herzig and colleagues estimate that 180,000 cases of hospital-acquired pneumonia and 33,000 deaths each year may be due to their use.

The researchers conclude that the routine use of acid-suppressing drugs in non-ventilated, non ICU-treated patients with a low risk for developing stress ulcers should be re-examined.

Acid-Reducing Drugs and Pneumonia

There are several theories about how acid-reducing drugs might make patients more vulnerable to pneumonia.

By reducing the acid load in the stomach, the drugs may promote the growth of different bacteria in the upper gastrointestinal and upper respiratory tract linked to pneumonia.

Or they may promote pneumonia by suppressing coughing, Herzig explains. Coughing is a frequent symptom of acid reflux and it also helps clear the lungs, which reduces pneumonia risk.

Pulmonary and critical care specialist J. Randall Curtis, MD, tells WebMD that the finding are compelling but the study does not prove a link between use of proton pump inhibitors and other acid-reducing drugs and pneumonia.

Curtis is president of the American Thoracic Society and a professor in the division of pulmonary and critical care medicine at the University of Washington. "While I would argue that the study is not conclusive, I would also say that it is a wake-up call to hospital-based physicians to really look at situations in which these medications are prescribed and ask themselves if they are, in fact, indicated."

Herzig adds that the pneumonia risk to hospitalized and non-hospitalized people who have clear indications for taking acid-suppressing drugs is minimal.

"Patients who are taking these medications for symptoms such as frequent heartburn or ulcers should not stop taking them," she says. "The risk to these patients is very small."

Show Sources


Herzig, S.J. The Journal of the American Medical Association, May 27, 2009; vol 301: pp 2120-2128

Shoshana J. Herzig, MD, instructor in medicine, Harvard Medical School, Boston.

J. Randall Curtis, MD, president, American Thoracic Society; professor of medicine, division of pulmonary and critical care medicine, University of Washington; head of pulmonary and critical care unit, Harborview Medical Center, Seattle.

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