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Table 1 Summary of the two included studies

From: Cilostazol for the prevention of pneumonia: a systematic review

Study and country

Yamaya et al. 2001 [16], Japan

Shinohara et al. 2006 [10], Japan

Population

History of cerebral infarction but not bedridden

History of cerebral infarction, age < 80 years

Mean age

Mean age: 76.5 ± 2.1 years

Mean age: 65.0 ± 8.7 years

Gender

No statement about gender

Female 34.4%

Risk factors

No statement about risk factors for pneumonia

No statement about risk factors for pneumonia

Criteria for diagnosis of pneumonia

New pulmonary infiltrate seen on chest radiographs (assessed by two radiologists not involved in the study) and one of the following: cough, body temperature > 37.8 °C, subjective dyspnea

Description by attending physician in the medical chart, chest radiographs and blood test

Intervention and control (n, allocated)

I: cilostazol 100 mg per day (n: not stated)

I: cilostazol 200 mg per day (n: 547)

C: no active treatment (n: not stated)

C: placebo (n: 548)

328 patients were allocated in total but the number of patients in each group at allocation was not reported

 

Intervention period

3 years

3.3 years on average

Number of patients analyzed

I = 125, C = 145, see comments

I = 531, C = 533, see comments

Outcomes

Pneumonia

Pneumonia

I: 12 (9.6%), C: 35 (24.1%)

I: 3 (0.56%), C: 15 (2.8%)

RR = 0.40 (95% CI 0.22–0.73)**

RR = 0.20 (95% CI 0.06–0.69)**

Cerebral infarction

Cerebral infarction [17]

I: 9 (7.2%), C: 24 (16.6%)

I: 30 (5.6%), C: 57 (10.7%)

RR = 0.43 (95% CI 0.21–0.90)*

RR = 0.53 (95% CI 0.34–0.81)*

Bleeding

Bleeding [17]

I: 12 (9.6%), severity of the bleeding events was not reported

Fatal intracranial hemorrhage

C: No statement about adverse events

I: 0, C: 1

 

Nonfatal intracranial hemorrhage

 

I: 4 (0.75%), C: 6 (1.1%)

 

Other bleeding

 

I: 15a (2.8%), C: 11 (2.1%)

Risk of bias

Random sequence generation

Low

Low

Allocation concealment

Unclear: Inadequate description

Low

Blinding of participants and personnel

High: Open-label trial

Low

Blinding of outcome assessment

Low

Unclear: Post-hoc analysis of a RCT [17]

Incomplete outcome data

High: As-treated analysis

Unclear: Reasons for dropouts were unclear

Selective reporting

High: No protocol available, No statement about adverse events in the control group

High: Post-hoc analysis of a RCT [17]

Other bias

Unclear: No statement about funding

Unclear: No statement about funding but original RCT [17] was supported by Otsuka Pharmaceutical

Comments

Reported in a Letter to the Editor

1095 patients were randomized but 31 patients were excluded from analysis because of “serious protocol violations”

328 patients were randomized but 58 patients were excluded from analysis; 31 patients died from causes other than pneumonia; additionally, 27 patients in cilostazol group dropped out because of adverse events

Of 1064 patients, about half of the patients discontinued the treatment (I: 54%, C: 49%)

  1. C control, CI confidence interval, I intervention, RR risk ratio
  2. *P < 0.05, **P < 0.01
  3. a Including one gastrointestinal bleeding