I would like to thank S. Teramoto and co-workers for their response to the study my co-workers and I performed on the effects of angiotensin-converting enzyme (ACE) inhibitors on the risk of acquiring pneumonia. Indeed, we could not confirm an association between the use of ACE inhibitors and the risk of pneumonia in a general population. This, however, does not exclude any beneficial effects of ACE inhibitors in specified patient subgroups.
As mentioned in our introduction and by S. Teramoto and co-workers, it is known that patients with a history of stroke do have a higher risk of acquiring pneumonia, which is particularly due to a reduced cough and swallowing reflex 1, 2. That ACE inhibitors can be beneficial in these patients is already widely reported 3–5. We aimed to study whether this protective effect can also be extended to the general population. Unfortunately, we were not able to test modification of the association through stroke, as data on stroke history were sparsely available in the database.
Concerning ethnicity, the reason why the association could not be confirmed in the non-Asian participants of the Perindopril Protection Against Recurrent Stroke Study (PROGRESS) is still subject to speculation. Genetic differences should certainly be considered. However, Ohkubo et al. 4 were unable to show an influence of the ACE I/D polymorphism on the protective association. Another explanation could be the higher prevalence of ACE inhibitor-induced cough in Chinese subjects, as shown by Chan et al. 6. It is possible that ACE inhibitors are also protective in non-Asian populations. However, larger populations may be necessary to confirm such an effect.
Further studies on the relationship between angiotensin-converting enzyme and pneumonia in predominantly white populations are currently being undertaken in our department.
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