Exeter, UK—Older adults taking stomach acid–reducing medication have an increased risk of pneumonia in the second year of their drug use, according to a longitudinal analysis of British electronic medical records.

Proton pump inhibitors (PPIs), prescribed to more than a third of older adults, have been linked to increased rates of a range of conditions, including fractures, cardiovascular disease, and some bacterial infections, notes the report in the Journal of the American Geriatrics Society.

Researchers at the University of Exeter sought to determine the association between use of PPIs and pneumonia because stomach acid can be a barrier to infections spreading from the gut. They also emphasize that pneumonia is a major cause of death for older adults.

To find out whether a link exists, the study team searched a large database, the Clinical Practice Research Datalink for England, to identify more than 75,000 patients aged 60 years and older in primary care receiving PPIs for a year or longer and compared them with a similar number of sex- and age-matched controls. The prior event rate ratio (PERR), which adjusts for pneumonia incidence differences before initiation of treatment, was used to estimate net hazard ratios for pneumonia incidence in Year 2 of treatment.

“During the second year after initiating treatment, PPIs were associated with greater hazard of incident pneumonia (PERR-adjusted hazard ratio=1.82, 95% confidence interval=1.27–2.54), accounting for pretreatment pneumonia rates,” researchers reported.

“Estimates were similar across age and comorbidity subgroups. Similar results were also obtained from propensity score– and inverse probability–weighted models.”

“This study shows that there was a higher rate of pneumonia in older people who received PPIs over a two-year period,” co-author David Melzer, MBBCh, PhD, pointed out. “Caution is needed in interpreting the findings as our study is based on analyzing data from medical records, so other factors may be involved. However, our study adds to growing evidence that PPIs are not quite as safe as previously thought, although they are still a very useful class of medication for certain groups of patients.”

Background information in the articles noted that about 40% of older adults receive PPIs, although past research has suggested that as many as 85% of them might be taking the drugs unnecessarily.

“In a large cohort of older adults in primary care, PPI prescription was associated with greater risk of pneumonia in the second year of treatment. Results were robust across alternative analysis approaches,” study authors concluded. “Controversies about the validity of reported short-term harms of PPIs should not divert attention from potential long-term effects of PPI prescriptions on older adults.”