ACE inhibitors and pneumonia in elderly people

Abstract

In hypertensive patients with stroke and silent aspirations, treatment with an inhibitor of angiotensin-converting enzyme (ACE) (imidapril hydrochloride)1Saluta T Omae T Kuramochi M et al.Imidapril hydrochloride in essential hypertension: a double-blind comparative study using enarapril malates as a control.J Hypertens. 1995; 13: 23-30Google Scholar led to increased concentrations of substance P and improvement in symptomless dysphagia.2Arai T Yasuda Y Takaya T et al.ACE inhibitors and symptomless dysphagia.Lancet. 1998; 352: 115-116Summary Full Text Full Text PDF PubMed Scopus (61) Google Scholar Symptomless dysphagia is one of the main causes of pneumonia in elderly people with stroke, and swallowing or the cough reflex can prevent aspiration pneumonia.3Sekizawa K Ujiie Y Itabashi S Sasaki H Takishima T Lack of cough reflex in aspiration pneumonia.Lancet. 1990; 335: 1228-1229Abstract PubMed Scopus (168) Google Scholar An important reduction in substance P concentration might contribute to the reduced respiratory tract reflexes.4Tomaki M Ichinose M Mirua M et al.Angiotensin converting enzyme (ACE) inhibitor-induced cough and substance P.Thorax. 1996; 51: 199-201Crossref PubMed Scopus (57) Google Scholar After treatment with ACE inhibitors, substance P increases with subsequent improvement in the respiratory tract reflexes. Kiyohisa Sekizawa and colleagues (Sept 26, p 1069)5Sekizawa K Matsui T Nakagawa T Nakaya K Sasaki H ACE inhibitors and pneumonia.Lancet. 1998; 352: 1069Summary Full Text Full Text PDF PubMed Scopus (137) Google Scholar report that ACE inhibitors decreased pneumonia in patients with a history of stroke. We investigated the relation between ACE inhibitors and prevention of pneumonia in elderly people. In 189 men (mean age 75·3 years) and 387 women (76·5 years) age 65 years or older, we examined inhibitory activity of ACE inhibitors against aspiration pneumonia. 269 (125 men and 144 women) of the 516 hypertensive patients were given the ACE inhibitor imidapril hydrochloride and 247 (108 men, 139 women) were given a calcium-channel blocker. 60 nonhypertensive patients served as controls. The rate of pneumonia was compared in these three groups for 3 years, from January, 1995, to May, 1998. Follow-up of these patients showed that there were nine (3·3%) patients with pneumonia in the group on ACE inhibitors, 22 (8·9%) in the group given calcium-channel blockers and five (8·3%) in the control group. The rate of pneumonia in the ACEinhibitor-treated group was significantly lower than that in the calcium-channel-blocker-treated group (Tukey's multiple comparison test, p=0·025). These results suggest that treatment of elderly hypertensive patients with ACE inhibitors might inhibit aspiration pneumonia.