title: Association between pneumococcal vaccination and cardiovascular outcomes: a systematic review and meta-analysis of cohort studies.
abstract: OBJECTIVE
  Streptococcus pneumoniae is the most common cause of community-acquired pneumonia (CAP) and CAP-related mortality in adults. Pneumococcal vaccination (PV) could protect subjects from cardiovascular events by reducing pneumonia severity or even preventing it. We sought to determine the ability of PV to protect from the risk of cardiovascular events.
  
  
  RESULTS
  A comprehensive search of electronic databases was conducted up to March 2014. Cohort studies that reported relative risk (RR) estimates with 95% confidence intervals (CI) were included. Eleven studies were included (332,267 participants, mean follow-up 20.1 months). The pooled RRs for cardiovascular events and cardiovascular mortality were 0.86 (95% CI: 0.76-0.97) and 0.92 (95% CI: 0.86-0.98; fixed-effects), respectively, for subjects with PV versus without PV. Protective ability was more prominent in high cardiovascular risk populations and with older age. The protective role of PV was attenuated after 1 year (RR: 0.72; 95% CI: 0.59-0.88 vs RR: 1.03; 95% CI: 0.93-1.14; p = 0.002, for follow-up >1 year vs ≤1 year, respectively). It also increased as the presence of cardiovascular and pulmonary disease increased. Regarding myocardial infarction (MI) and cerebrovascular events, the protective role of PV was statistically significant only in the elderly (RR: 0.90; 95% CI: 0.817-0.999; fixed-effects and RR: 0.86; 95% CI: 0.75-0.99, respectively).
  
  
  CONCLUSIONS
  PV is associated with decreased risk of cardiovascular events and mortality. This protective effect increases at older age and in high cardiovascular risk subjects and decreases as the time elapses from PV. PV decreases the risk of MI and cerebrovascular events in the elderly.
authors.affiliation: Peripheral Vessels Unit, 1st Department of Cardiology, Athens Medical School, Hippokration Hospital, Athens, Greece cvlachop@otenet.gr.
authors.forename: Charalambos V
authors.initials: CV
authors.lastname: Vlachopoulos
authors.affiliation: Peripheral Vessels Unit, 1st Department of Cardiology, Athens Medical School, Hippokration Hospital, Athens, Greece.
authors.forename: Dimitrios G
authors.initials: DG
authors.lastname: Terentes-Printzios
authors.affiliation: Peripheral Vessels Unit, 1st Department of Cardiology, Athens Medical School, Hippokration Hospital, Athens, Greece.
authors.forename: Konstantinos A
authors.initials: KA
authors.lastname: Aznaouridis
authors.affiliation: Peripheral Vessels Unit, 1st Department of Cardiology, Athens Medical School, Hippokration Hospital, Athens, Greece.
authors.forename: Panagiota G
authors.initials: PG
authors.lastname: Pietri
authors.affiliation: Peripheral Vessels Unit, 1st Department of Cardiology, Athens Medical School, Hippokration Hospital, Athens, Greece.
authors.forename: Christodoulos I
authors.initials: CI
authors.lastname: Stefanadis
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002318:Cardiovascular Diseases / Q000382:microbiology / Q000401:mortality / Q000517:prevention & control*; D017714:Community-Acquired Infections / Q000150:complications / Q000382:microbiology / Q000401:mortality / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D011018:Pneumonia, Pneumococcal / Q000150:complications / Q000382:microbiology / Q000401:mortality / Q000517:prevention & control*; D065840:Protective Factors; D018570:Risk Assessment; D012307:Risk Factors; D013296:Streptococcus pneumoniae / Q000472:pathogenicity*; D013997:Time Factors; D016896:Treatment Outcome; D014611:Vaccination
chemical_list: D022242:Pneumococcal Vaccines
keywords: Pneumococcal vaccination; cardiovascular disease; cardiovascular mortality; meta-analysis; myocardial infarction; stroke