title: Pneumococcal pneumonia and the risk of stroke: a population-based follow-up study.
abstract: BACKGROUND
  To investigate the risk of developing stroke in patients hospitalized following a diagnosis of pneumococcal pneumonia.
  
  
  METHODS
  The study cohorts comprised of patients hospitalized with a principal diagnosis of pneumococcal pneumonia (n  = 745), with a random sampling of control individuals in 2004 (n  = 1490). The Cox proportional hazard model was used to compare the stroke-free survival rate between the cohorts after adjusting for possible confounding and risk factors for a two-year follow up. Instrumental variable analysis (IVA) was used to address potential biases associated with measured and unmeasured confounding variables.
  
  
  RESULTS
  Of the 153 patients with stroke, 80 (10.7%) were from the pneumococcal pneumonia cohort, and 73 (4.9%) were from the control group. The risk of stroke was 3.65 times higher (95% confidence interval, 2.25-5.90; P<0.001) in patients with pneumococcal pneumonia after adjusting for patient characteristics, co-morbidities, geographic region, urbanization level of residence, and socioeconomic status during the first year. IVA showed an additional 14% risk of stroke for pneumococcal pneumonia patients (odds ratio = 1.14; 95% CI, 1.02-1.26, P = 0.032).
  
  
  CONCLUSIONS
  Patients with pneumococcal pneumonia carry an increased risk for stroke than the general population. Further studies are warranted for developing better diagnostic and follow-up strategies for patients with increased risk.
authors.affiliation: Department of Emergency Medicine, National Yang-Ming University Hospital, I-Lan, Taiwan.
authors.forename: Li-Fu
authors.initials: LF
authors.lastname: Chen
authors.forename: Hsin-Pai
authors.initials: HP
authors.lastname: Chen
authors.forename: Yung-Sung
authors.initials: YS
authors.lastname: Huang
authors.forename: Kuang-Yung
authors.initials: KY
authors.lastname: Huang
authors.forename: Pesus
authors.initials: P
authors.lastname: Chou
authors.forename: Ching-Chih
authors.initials: CC
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D015897:Comorbidity; D003710:Demography; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D011018:Pneumonia, Pneumococcal / Q000150:complications*; D016016:Proportional Hazards Models; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology* / Q000209:etiology*; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult