title: Diurnal variation in mortality in older nocturnal fallers.
abstract: BACKGROUND
  The prevalence of older trauma patients is rising in Westernised populations. Age has an independent adverse affect on survival from injury. Factors contributing to this increased mortality are incompletely understood.
  
  
  OBJECTIVE
  To examine the independent effects of age, time and mechanism of injury on survival from trauma at 30 days.
  
  
  METHODS
  We analysed prospectively collected data from the Trauma Audit and Research Network database. Isolated femoral neck and pubic rami fractures are not included in this data set. Univariate and multivariate regression analyses were undertaken. Independent effects of age, time of injury and mechanism of injury on survival following trauma were evaluated.
  
  
  RESULTS
  A total of 137,521 trauma patients were included in the study. Trauma victims aged over 65 years had increased odds of death of 9.58 (95% CI: 8.78-10.45), adjusting for known confounders of outcome. Analysis of two-way interactions of age and time of arrival to hospital, revealed patients ≥65 years had a higher odds of death if they presented between midnight and 8 a.m., compared with 08:00-16:00 h; OR = 1.5, (95% CI: 1.29-1.73). Further analysis of this older group, examining the interaction of time and mechanism of injury, revealed a doubling of the odds of death in patients injured following a fall <2 m, when they presented between midnight and 8 a.m.; OR = 2.1, (95% CI: 1.32-3.30). This diurnal variation in mortality was exclusive to older fallers.
  
  
  CONCLUSIONS
  Age over 65 years has an independent detrimental affect on survival from trauma. A distinct diurnal variation in mortality from injury occurs in older patients injured as a result of a low velocity fall.
authors.affiliation: Emergency Department, Emergency Medicine, Trinity College Dublin, St James's Hospital, Dublin 8, Ireland. geraldinemcmahon@upcmail.ie
authors.forename: Christine Geraldine
authors.initials: CG
authors.lastname: McMahon
authors.forename: Rose Anne
authors.initials: RA
authors.lastname: Kenny
authors.forename: Kathleen
authors.initials: K
authors.lastname: Bennett
authors.forename: Omar
authors.initials: O
authors.lastname: Bouamra
authors.forename: Fiona
authors.initials: F
authors.lastname: Lecky
mesh_terms: D000058:Accidental Falls / Q000401:mortality*; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002940:Circadian Rhythm; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016019:Survival Analysis; D015599:Trauma Severity Indices; D016896:Treatment Outcome