Acid suppressants linked to pneumonia risk

Hospitalised patients who are given acid-suppressive medication have a 30% increased risk of developing pneumonia during their admission, a large American study has found. Published in JAMA, the study examined over 42 000 unique hospital admissions that lasted for over three days and found that acid-suppressive medication was ordered in 52% of admissions. After adjustment, the odds ratio of hospital-acquired pneumonia for patients who were exposed to acid-suppressive medication was 1.3. Patients who were exposed to acid-suppressive medication were also more likely to develop aspiration pneumonia than nonaspiration pneumonia (ORs 1.4 and 1.2 respectively). When the results were analysed according to different types of acid-suppression medication, proton-pump inhibitors showed a statistically significant association with pneumonia while histamine2 receptor antagonists did not. However, the study’s authors noted that the smaller number of patients given the histamine2 receptor antagonists (7548 vs 27 236) meant that the subgroup analysis was not adequately powered to detect significance for an odds ratio of less than 1.3. The authors said that their findings were in line with an increasing body of literature suggesting an association between acid-suppressive medication and pneumonia. “With an estimated mortality rate of 18% for hospital-acquired pneumonia, exposure to these medications could result in 33 000 preventable deaths annually,” they said. However, they noted that while the medications have been thought to increase the risk of pneumonia via modification of the upper gastrointestinal flora, recent findings show that the risk of developing the condition is highest in the first 2 days of use, which would not be explained by this mechanism. Another possible explanation may be that impairment of white blood cell function, which occurs within hours of use of acid-suppressive medications, may increase the risk of developing pneumonia, they said. JAMA. 2009;301(20):2120-2128...