title: Community-acquired bacterial meningitis: risk stratification for adverse clinical outcome and effect of antibiotic timing.
abstract: BACKGROUND
  Community-acquired bacterial meningitis causes substantial morbidity and mortality in adults.
  
  
  OBJECTIVE
  To create and test a prognostic model for persons with community-acquired bacterial meningitis and to determine whether antibiotic timing influences clinical outcome.
  
  
  METHODS
  Retrospective cohort study; patients were divided into derivation and validation samples.
  
  
  METHODS
  Four hospitals in Connecticut.
  
  
  METHODS
  269 persons who, between 1970 and 1995, had community-acquired bacterial meningitis microbiologically proven by a lumbar puncture done within 24 hours of presentation in the emergency department.
  
  
  METHODS
  Baseline clinical and laboratory features and times of arrival in the emergency department, performance of lumbar puncture, and administration of antibiotics. The target end point was the development of an adverse clinical outcome (death or neurologic deficit at discharge).
  
  
  RESULTS
  For the total group, the hospital mortality rate was 27%. Fifty-six of 269 patients (21 %) developed a neurologic deficit, and in 9% the neurologic deficit persisted at discharge. Three baseline clinical features (hypotension, altered mental status, and seizures) were independently associated with adverse clinical outcome and were used to create a prognostic model from the derivation sample. The prediction accuracy of the model was determined by using the concordance index (c-index). For both the derivation sample (c-index, 0.73 [95% CI, 0.65 to 0.81]) and the validation sample (c-index, 0.81 [CI, 0.71 to 0.92]), the model predicted adverse clinical outcome significantly better than chance. For the total group, the model stratified patients into three prognostic stages: low risk for adverse clinical outcome (9%; stage I), intermediate risk (33%; stage II), and high risk (56%; stage III) (P=0.001). Adverse clinical outcome was more common for patients in whom the prognostic stage advanced from low risk (P=0.008) or intermediate risk (P=0.003) at arrival in the emergency department to high risk before administration of antibiotics.
  
  
  CONCLUSIONS
  In persons with community-acquired bacterial meningitis, three baseline clinical features of disease severity predicted adverse clinical outcome and stratified patients into three stages of prognostic severity. Delay in therapy after arrival in the emergency department was associated with adverse clinical outcome when the patient's condition advanced to the highest stage of prognostic severity before the initial antibiotic dose was given.
authors.affiliation: Waterbury Hospital, Connecticut 06721, USA.
authors.forename: S I
authors.initials: SI
authors.lastname: Aronin
authors.forename: P
authors.initials: P
authors.lastname: Peduzzi
authors.forename: V J
authors.initials: VJ
authors.lastname: Quagliarello
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000150:complications / Q000188:drug therapy* / Q000401:mortality; D003237:Connecticut / Q000453:epidemiology; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D016015:Logistic Models; D008297:Male; D016920:Meningitis, Bacterial / Q000150:complications / Q000188:drug therapy* / Q000401:mortality; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D013223:Statistics as Topic; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents