Cilostazol for the prevention of pneumonia: a systematic review

Hirotaka Nakashima, Kazuhisa Watanabe, Hiroyuki Umegaki, Yusuke Suzuki, Masafumi Kuzuya

Pneumonia is a very common disease, especially among the elderly. Various drugs' preventive effects against pneumonia have been reported. The antiplatelet drug cilostazol is used to prevent pneumonia, but the robustness of its efficacy is unclear. This review estimates the effectiveness of cilostazol for preventing pneumonia in elderly individuals. The following databases were searched from the earliest record to January 2016, without language restriction (the secondary search was conducted on February 2017): MEDLINE, Cochrane Library, CINAHL, and Ichushi-Web. Studies were included if they were published randomized controlled trials investigating the preventive effect of cilostazol on pneumonia in the elderly. The outcome was the incidence of pneumonia. Two trials were identified that met the search criteria (1423 participants). Both trials compared cilostazol with no antiplatelet in patients with a history of cerebral infarction. A meta-analysis was not performed because of the small number of trials and the heterogeneity of the data. Both trials suggested that cilostazol reduced the incidence of pneumonia (risk ratio [RR] 0.40; 95% confidence interval [CI] 0.22-0.73 in one trial, RR 0.20; 95% CI 0.06-0.69 in the other) and the recurrence of cerebral infarction (0.43; 0.21-0.90, 0.53; 0.34-0.81, respectively). The quality of evidence provided by the trials was very low, mainly because of the high risk of bias. It is difficult to draw conclusions on the basis of two trials. Moreover, in the two trials, cilostazol could have reduced the incidence of pneumonia via a reduction of the recurrence of cerebral infarction, which suggests that other antiplatelets could also have the same effects. Stronger evidence is required from large trials assessing the effectiveness of cilostazol for the prevention of pneumonia. PROSPERO (CRD42016036724).