Reduction of gastric acid secretion by acid-suppressive therapy allows pathogen colonization from the upper gastrointestinal tract.
The bacteria and viruses in the contaminated stomach have been identified as species from the oral cavity.
Dr Robert Laheij and colleagues from the Netherlands undertook a study to examine the association between the use of acid-suppressive drugs and occurrence of community-acquired pneumonia.
The research group identified incident acid-suppressive drug users with at least 1 year of valid database history from the Integrated Primary Care Information database between January 1, 1995, and December 31, 2002.
The researchers calculated incidence rates for pneumonia for unexposed and exposed individuals.
In order to reduce confounding by indication, the research team conducted a case-control analysis nested in a cohort of incident users of acid-suppressive drugs.
|Current users of H2-receptor antagonists had a 1.63-fold increased risk of pneumonia compared with those who stopped use|
|Journal of the American Medical Association|
Cases were all individuals with incident pneumonia during or after stopping use of acid-suppressive drugs.
The researchers ensured that there were up to 10 controls matched to each case for practice, year of birth, sex, and index date.
The group used conditional logistic regression to compare the risk of community-acquired pneumonia between use of proton pump inhibitors (PPIs) and H2-receptor antagonists.
The researchers defined community-acquired pneumonia as certain (proven by radiography or sputum culture) or probable (clinical symptoms consistent with pneumonia).
In total, the research team studied a population that comprised of 364 683 individuals who developed 5551 first occurrences of pneumonia during follow-up.
The authors found that the incidence rates of pneumonia in non–acid-suppressive drug users and acid-suppressive drug users were 0.6 and 2.45 per 100 person-years, respectively.
The adjusted relative risk for pneumonia among persons currently using PPIs compared with those who stopped using PPIs was 1.89.