title: Prevalence of Influenza Vaccination in Chronic Obstructive Pulmonary Disease Patients and Impact on the Risk of Severe Exacerbations.
abstract: OBJECTIVE
  To determine the prevalence of influenza vaccination in chronic obstructive pulmonary disease (COPD) patients, and the effectiveness of the procedure.
  
  
  METHODS
  Retrospective population-based cohort study. On 31 December 2011, influenza vaccination history was retrieved from 899 patients with confirmed COPD selected by simple random sampling from all COPD patients in Cantabria (northern Spain). Severe exacerbations (hospitalization due to COPD exacerbation) and overall mortality during 2012 were treated as dependent variables. Odds ratios (OR) were estimated by logistic regression, adjusting for age, sex, smoking status, severity of COPD, and frequency of exacerbations during the previous year. Prevented fraction among the exposed (PFe-adjusted) was determined as a measure of impact.
  
  
  RESULTS
  Overall prevalence of influenza vaccination was 62.7%, but this rate fell in patients classified as more severe according to FEV1 (52.0%). Influenza vaccination showed a statistically significant protective effect against severe exacerbations in the following year: Ora: 0.54 (95%CI: 0.35-0.84); FPe-adjusted: 0.46 (95%CI: 0.16-0.65). A non-significant protective effect for overall mortality was observed: Ora: 0.76 (95%CI: 0.41-1.40). When stratified according to COPD severity (FEV1), the protective effect against risk of hospitalization was higher in more severe COPD patients: Ora: 0.23 (95%CI: 0.11-0.48); FPe-adjusted: 0.77 (95%CI: 0.52-0.89).
  
  
  CONCLUSIONS
  We found that influenza vaccination has a protective effect and reduces the risk of hospitalization due to exacerbations in the following year. Despite the evidence for protection, prevalence of vaccination was not optimal, especially in more severe COPD patients.
authors.affiliation: Centro de Salud de Gama, Servicio Cántabro de Salud, Bárcena de Cicero, Cantabria, España.
authors.forename: Roberto
authors.initials: R
authors.lastname: Garrastazu
authors.affiliation: Servicio de Neumología, Hospital Laredo, Laredo, Cantabria, España.
authors.forename: Juan Luis
authors.initials: JL
authors.lastname: García-Rivero
authors.affiliation: Centro de Salud de Liérganes, Servicio Cántabro de Salud, Miera, Cantabria, España.
authors.forename: Mario
authors.initials: M
authors.lastname: Ruiz
authors.affiliation: Centro de Salud Bajo Asón, Servicio Cántabro de Salud, Ampuero, Cantabria, España.
authors.forename: Jose Manuel
authors.initials: JM
authors.lastname: Helguera
authors.affiliation: Centro de Salud de Suances, Servicio Cántabro de Salud, Suances, Cantabria, España.
authors.forename: Sandra
authors.initials: S
authors.lastname: Arenal
authors.affiliation: Centro de Salud Campoo-Los Valles, Servicio Cántabro de Salud, Mataporquera, Cantabria, España.
authors.forename: Cristina
authors.initials: C
authors.lastname: Bonnardeux
authors.affiliation: Centro de Salud de Suances, Servicio Cántabro de Salud, Suances, Cantabria, España.
authors.forename: Carlos
authors.initials: C
authors.lastname: León
authors.affiliation: Área de Medicina Preventiva y Salud Pública, Universidad de Cantabria-IDIVAL, Santander, España.
authors.forename: Javier
authors.initials: J
authors.lastname: Llorca
authors.affiliation: Área de Medicina Preventiva y Salud Pública, Universidad de Cantabria-IDIVAL, Santander, España. Electronic address: santibanezm@unican.es.
authors.forename: Miguel
authors.initials: M
authors.lastname: Santibañez
mesh_terms: D000368:Aged; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D014611:Vaccination / Q000706:statistics & numerical data*
chemical_list: D007252:Influenza Vaccines
keywords: Chronic obstructive pulmonary disease; Enfermedad pulmonar obstructiva crónica; Influenza vaccines; Prevención primaria; Primary prevention; Vacunación antigripal