title: Validation of a severity-of-illness score in patients with tuberculosis requiring intensive care unit admission.
abstract: BACKGROUND
  There is a paucity of data on the determinants of mortality due to tuberculosis (TB) in the intensive care unit (ICU).
  
  
  OBJECTIVE
  To develop a simple severity-of-illness score for use in patients with TB admitted to an ICU.
  
  
  METHODS
  A scoring system was generated by retrospectively identifying the four most significant and clinically unrelated predictors of mortality from an existing prospectively collected dataset (January 2012 - May 2013), and combining these with known predictors of poor outcome.
  
  
  RESULTS
  Of 83 patients admitted with TB, 38 (45.8%) died in the ICU. The four parameters identified from the retrospective analysis were: (i) HIV co-infection with a CD4cell count &lt;200/µL; (ii) a raised creatinine level: (iii) a chest radiograph showing diffuse parenchymal infiltrates/miliary pattern; and (iv) absence of TB treatment on admission. These were combined with septic shock and a low arterial partial pressure of oxygen/fractional inspired oxygen (P:F) ratio to generate a six-point severity-of-illness score (one point for each parameter). The scores for survivors were significantly lower than those for non-survivors (mean (standard deviation) 2.27 (1.47) v. 3.58 (1.08); p&lt;0.01). A score of ≥2 was associated with significantly higher mortality than a score of &lt;2 (7.1% v. 46.4%; odds ratio (OR) 15.03; 95% confidence interval (CI) 1.86 - 121.32; p&lt;0.01), whereas a score of ≥3 was associated with a significantly higher mortality than a score of &lt;3 (64.6% v. 20.0%; OR 7.29; 95% CI 2.64 - 20.18; p&lt;0.01).
  
  
  CONCLUSIONS
  The proposed scoring system identified patients at increased risk of dying from TB in the ICU. Further prospective studies are indicated to validate its use.
authors.affiliation: Division of Pulmonology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University and Tygerberg Academic Hospital, Tygerberg, Cape Town, South Africa. coeniefn@sun.ac.za.
authors.forename: Coenraad Frederik N
authors.initials: CF
authors.lastname: Koegelenberg
authors.forename: Cecile A
authors.initials: CA
authors.lastname: Balkema
authors.forename: Ynishia
authors.initials: Y
authors.lastname: Jooste
authors.forename: Jantjie J
authors.initials: JJ
authors.lastname: Taljaard
authors.forename: Elvis M
authors.initials: EM
authors.lastname: Irusen
mesh_terms: D005260:Female; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D015994:Incidence; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D010343:Patient Admission; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology