Summary results of studies included in the meta-analysis
| Authors (year) | Jackson et al (2002) | Hung et al (2010) | Tseng et al (2010) | Eurich et al (2012) | Vila-Corcoles et al (2014) Ochoa-Gondar et al (2014) | Meyers et al (2004) | Lamontagne et al (2008) | Siriwardena et al (2010) | Siriwardena et al(2014) |
|---|---|---|---|---|---|---|---|---|---|
| Study type | Cohort | Cohort | Cohort | Cohort | Cohort | Case–control | Case–control | Case–control | Case–control |
| Newcastle-Ottawa quality scale | |||||||||
| Selection | 3/4 | 3/4 | 3/4 | 2/4 | 3/4 | 3/4 | 2/4 | 2/4 | 3/4 |
| Comparability | 2/2 | 0/2 | 2/2 | 2/2 | 2/2 | 1/2 | 1/2 | 2/2 | 2/2 |
| Outcome (cohort)/exposure (case–control) | 3/3 | 3/3 | 2/3 | 3/3 | 3/3 | 2/3 | 3/3 | 3/3 | 3/3 |
| 1st outcome recorded (cohort)/intervention exposed to (case–control) | Recurrent cardiac event* | AMI | AMI (age ≥65) | Composite ACS† (propensity-matched)‡ | AMI | PPV | PPV only§ | PPV (age ≥65) | PPV (age ≥65) |
| Number of events or event rate (cohort), exposure to intervention (case–control) | 21/1000 p-y (PPV only), 21/1000 p-y (unvaccinated) | 25/724 (PPV), 54/724 (unvaccinated) | 136/8981 (PPV), 223/18 223 (unvaccinated) | 107/335 (cases), 78/199 (controls) | 71/199 (cases), 465/3996 (controls) | 5531/10 671 (cases), 20 134/41 335 (controls) | 14 835/20 522 (cases), 15 394/20 522 (controls) | ||
| Most adjusted ratio | aHR=1.08 | aHR=0.79 | aHR=0.89 | aHR=0.46 | aHR=1.04 | aOR=0.89 | aOR=0.53 | aOR=0.97 | aOR=1.00 |
| 95% CI | 0.73–1.59 | 0.48–1.28 | 0.80–1.01 | 0.28–0.73 | 0.83–1.31 | 0.60–1.33 | 0.40–0.70 | 0.91–1.03 | 0.94–1.05 |
| 2nd outcome/intervention recorded | Ischaemic stroke | Stroke (age ≥65) | Composite ACS† | Ischaemic stroke | PPV (all ages) | PPV (all ages) | |||
| Number of events or event rate (cohort), exposure to intervention (case–control) | 25/1000 p-y (PPV only), 36/1000 p-y (unvaccinated) | 25/725 (PPV), 150/5446 (unvaccinated) | 133/8981 (PPV), 210/18 223 (unvaccinated) | 6153/16 012 (cases), 21 734/62 694 (controls) | 17 206/26 784 (cases), 16 773/26 784 (controls) | ||||
| Most adjusted ratio | aHR=0.79 | aHR=0.85 | aHR=0.42 | aHR=0.97 | aOR=0.98 | aOR=0.96 | |||
| 95% CI | 0.54–1.14 | 0.70–1.03 | 0.27–0.66 | 0.77–1.23 | 0.93–1.04 | 0.92–1.02 | |||
| 3rd outcome recorded | AMI (all ages) | Composite ACS+ (age ≥65) | |||||||
| Number of events or event rate | 1724/36 309 (PPV), 981/47 861 (unvaccinated) | ||||||||
| Most adjusted ratio | aHR=1.09 | aHR=0.44 | |||||||
| 95% CI | 0.98–1.21 | 0.28–0.69 | |||||||
| 4th outcome recorded | Stroke (all ages) | ||||||||
| Number of events or event rate | 799/36 309 (PPV), 335/47 861 (unvaccinated) | ||||||||
| Most adjusted ratio | aHR=1.14 | ||||||||
| 95% CI | 1.00–1.31 | ||||||||
*Composite of non-fatal MI and atherosclerotic cardiovascular disease death, including MI, IHD, CHF, hypertensive heart disease, cardiac arrest and AF.
†Including myocardial infarction or unstable angina or death attributed to ACS.
‡The propensity-matched analysis (c-statistic=0.86) permitted 724 of the 725 (99.9%) patients exposed to PPV to be matched to 724 controls. Propensity (to receive PPV) score analysis was based on variables present before pneumonia onset that could be associated with the decision to administer PPV.
§Original study also included influenza vaccination as another intervention.
ACS, acute coronary syndrome; AF, atrial fibrillation; aHR, adjusted HR; AMI, acute myocardial infarction; aOR, adjusted OR; CHF, congestive heart failure; IHD, ischaemic heart disease; MI, myocardial infarction; PPV, pneumococcal polysaccharide vaccine; p-y, person-years.