Cohort | Subject n | Risk reduction | [Ref.] | |
Retrospective cohort study in teaching hospital | 787 | 0.36 (0.14–0.92) | 64% reduction in 30-day mortality | [102] |
Population based prospective cohort study | 3415 | 0.78 (0.57–1.07) | 22% reduction in mortality or admission to an ICU | [103] |
Population based retrospective nested case–control | 6089 | 0.47 (0.25–0.88) | 53% reduction in fatal pneumonia | [104] |
Prospective hospital based observational study | 1007 | 0.46 (0.25–0.85) | 54% reduction in 30-day mortality | [105] |
Population based cohort study | 29900 | 0.69 (0.58–0.82) | 31% reduction in 30-day mortality | [106] |
0.75 (0.65–0.86) | 25% reduction in 90-day mortality | |||
Retrospective national cohort study | 8652 | 0.54 (0.42–0.70) | 46% reduction in 30-day mortality | [107] |
Population based case–control study | 2235 | 0.81 (0.46–1.42) | 19% reduction in risk of pneumonia (after excluding those with CAD) | [108] |
Population based cohort study | 3681 | 0.33 (0.19–0.58) | 67% reduction in 30-day mortality | [109] |
0.45 (0.32–0.62) | 55% reduction in long-term mortality |
Data are presented as odds ratio (95% confidence interval). Data for population based case–control study and cohort study are presented as hazard ration (95% confidence interval). ICU: intensive care unit; CAD: coronary artery disease.