title: Community-acquired pneumonia on the intensive care unit: secondary analysis of 17,869 cases in the ICNARC Case Mix Programme Database.
abstract: BACKGROUND
  This paper describes the case mix, outcome and activity for admissions to intensive care units (ICUs) with community-acquired pneumonia (CAP).
  
  
  METHODS
  We conducted a secondary analysis of a high quality clinical database, the Intensive Care National Audit & Research Centre (ICNARC) Case Mix Programme Database, of 301,871 admissions to 172 adult ICUs across England, Wales and Northern Ireland, 1995 to 2004. Cases of CAP were identified from pneumonia admissions excluding nosocomial pneumonias and the immuno-compromised. It was not possible to review data from the time of hospital admission; therefore, some patients who developed hospital-acquired/nosocomial pneumonia may have been included.
  
  
  RESULTS
  We identified 17,869 cases of CAP (5.9% of all ICU admissions). There was a 128% increase in admissions for CAP from 12.8 per unit to 29.2 per unit during the study period compared to only a 24% rise in total ICU admissions (p < 0.001). Eighty-five percent of admissions were from within the same hospital. Fifty-nine percent of cases were admitted to the ICU < 2 days, 21.5% between 2 and 7 days, and 19.5% > 7 days after hospital admission. Between 1995 and 1999 and 2000 and 2004 there was a rise in admissions from accident and emergency (14.8% to 16.8%; p < 0.001) and high dependency units (6.9% to 11.9%; p < 0.001) within the same hospital, those aged > 74 (18.5 to 26.1%; p < 0.001), and mean APACHE II score (6.83 to 6.91; p < 0.001). There was a fall in past history of severe respiratory problems (8.7% to 6.4%; p < 0.001), renal replacement therapy (1.6% to 1.2%; p < 0.01), steroid treatment (3.4% to 2.8%; p < 0.05), sedation/paralysis (50.2% to 40.4%; p < 0.001), cardiopulmonary resuscitation prior to admission (7.5% to 5.5%; p < 0.001), and septic shock (7.3% to 6.6%; p < 0.001). ICU mortality was 34.9% and ultimate hospital mortality 49.4%. Mortality was 46.3% in those admitted to the ICU within 2 days of hospital admission rising to 50.4% in those admitted at 2 to 7 days and 57.6% in those admitted after 7 days following hospital admission.
  
  
  CONCLUSIONS
  CAP makes up a small, but important and rising, proportion of adult ICU admissions. Survival of over half of all cases vindicates the use of ICU facilities in CAP management. Nevertheless, overall mortality remains high, especially in those admitted later in their hospital stay.
authors.affiliation: Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL, UK. mark.woodhead@cmmc.nhs.uk
authors.forename: Mark
authors.initials: M
authors.lastname: Woodhead
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Welch
authors.forename: David A
authors.initials: DA
authors.lastname: Harrison
authors.forename: Geoff
authors.initials: G
authors.lastname: Bellingan
authors.forename: Jon G
authors.initials: JG
authors.lastname: Ayres
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017714:Community-Acquired Infections / Q000453:epidemiology; D016208:Databases, Factual; D003953:Diagnosis-Related Groups; D005260:Female; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data* / Q000639:trends; D008297:Male; D008875:Middle Aged; D010043:Outcome and Process Assessment, Health Care; D011014:Pneumonia / Q000453:epidemiology* / Q000628:therapy; D006113:United Kingdom / Q000453:epidemiology