title: Spinal infections in older people: an analysis of demographics, presenting features, microbiology and outcomes.
abstract: BACKGROUND
  Clinical features of infection can become more atypical as we age. Spinal infections can be insidious, and timely diagnosis and treatment are essential to prevent adverse outcomes.
  
  
  OBJECTIVE
  To explore differences in presentation and outcomes between younger and older patients with bacterial spinal infections.
  
  
  METHODS
  Clinical, microbiological and radiological information was collected for patients with spinal infections (spondylodiscitis, vertebral osteomyelitis, septic discitis, facet joint septic arthritis and spinal epidural abscess) at a single metropolitan hospital between January 2008 and January 2015. Patients were excluded if they were under 18 years of age or if clinical and imaging findings were inconsistent with the diagnosis. Presenting features, investigations and outcomes were compared for patients ≥65 (older) or <65 (younger) years old.
  
  
  RESULTS
  Of 53 identified patients, 34 (64%) were classified as older, with more males in both older (65%) and younger (79%) groups. Older patients presented later (median symptom duration 13 vs 4 days, P = 0.016). Back pain was nearly ubiquitous. Older patients presented less commonly with fevers (38 vs 63%) and rigors (24 vs 42%) but more commonly with hypotension (18 vs 5%), delirium (24 vs 11%), higher median inflammatory marker levels and variable microbiological findings, although these differences were not statistically significant. They had longer median lengths of stay (24 vs 14 days) and a higher likelihood of death or failure of medical treatment (HR 9.34, P = 0.031). Radicular pain was associated with poor outcome (HR 3.29, P = 0.046).
  
  
  CONCLUSIONS
  Older patients with spinal infections present later, with higher inflammatory markers and fewer typical infective symptoms and signs; these may contribute to poorer outcomes. A low threshold for promptly investigating older patients with new or worsening back pain should be set.
authors.affiliation: Department of Geriatric Medicine, Northern Health, Melbourne, Victoria, Australia.|Department of Geriatric Medicine, Alfred Health, Melbourne, Victoria, Australia.
authors.forename: S
authors.identifier: http://orcid.org/0000-0002-0522-6143
authors.initials: S
authors.lastname: Amadoru
authors.affiliation: Department of Geriatric Medicine, Northern Health, Melbourne, Victoria, Australia.|Department of Geriatric Medicine, Melbourne Health, Melbourne, Victoria, Australia.
authors.forename: K
authors.initials: K
authors.lastname: Lim
authors.affiliation: Northern Centre for Health Education and Research (NCHER), Northern Health, Melbourne, Victoria, Australia.|Melbourne EpiCentre, Department of Medicine, The University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Tacey
authors.affiliation: Department of Infectious Diseases, Northern Health, Melbourne, Victoria, Australia.|North West Academic Centre, Department of Medicine, The University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: C
authors.initials: C
authors.lastname: Aboltins
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001315:Australia; D001416:Back Pain / Q000209:etiology; D001424:Bacterial Infections / Q000453:epidemiology* / Q000628:therapy; D015415:Biomarkers; D005260:Female; D005334:Fever / Q000209:etiology; D006801:Humans; D053208:Kaplan-Meier Estimate; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D013122:Spinal Diseases / Q000453:epidemiology* / Q000382:microbiology* / Q000628:therapy; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D015415:Biomarkers
keywords: aged; back pain; epidural abscess; spinal infections; spondylodiscitis; vertebral osteomyelitis