title: Derivation and validation of a simple, accurate and robust prediction rule for risk of mortality in patients with Clostridium difficile infection.
abstract: BACKGROUND
  Clostridium difficile infection poses a significant healthcare burden. However, the derivation of a simple, evidence based prediction rule to assist patient management has not yet been described.
  
  
  METHODS
  Univariate, multivariate and decision tree procedures were used to deduce a prediction rule from over 186 variables; retrospectively collated from clinical data for 213 patients. The resulting prediction rule was validated on independent data from a cohort of 158 patients described by Bhangu et al. (Colorectal Disease, 12(3):241-246, 2010).
  
  
  RESULTS
  Serum albumin levels (g/L) (P = 0.001), respiratory rate (resps /min) (P = 0.002), C-reactive protein (mg/L) (P = 0.034) and white cell count (mcL) (P = 0.049) were predictors of all-cause mortality. Threshold levels of serum albumin ≤ 24.5 g/L, C- reactive protein >228 mg/L, respiratory rate >17 resps/min and white cell count >12 × 10(3) mcL were associated with an increased risk of all-cause mortality. A simple four variable prediction rule was devised based on these threshold levels and when tested on the initial data, yield an area under the curve score of 0.754 (P < 0.001) using receiver operating characteristics. The prediction rule was then evaluated using independent data, and yield an area under the curve score of 0.653 (P = 0.001).
  
  
  CONCLUSIONS
  Four easily measurable clinical variables can be used to assess the risk of mortality of patients with Clostridium difficile infection and remains robust with respect to independent data.
authors.forename: Emma
authors.initials: E
authors.lastname: Butt
authors.forename: Jane A H
authors.initials: JA
authors.lastname: Foster
authors.forename: Edward
authors.initials: E
authors.lastname: Keedwell
authors.forename: Julia E A
authors.initials: JE
authors.lastname: Bell
authors.forename: Richard W
authors.initials: RW
authors.lastname: Titball
authors.forename: Aneel
authors.initials: A
authors.lastname: Bhangu
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Michell
authors.forename: Ray
authors.initials: R
authors.lastname: Sheridan
mesh_terms: D000704:Analysis of Variance; D016360:Clostridioides difficile / Q000302:isolation & purification*; D003015:Clostridium Infections / Q000175:diagnosis / Q000453:epidemiology / Q000401:mortality*; D003663:Decision Trees; D005260:Female; D006801:Humans; D008297:Male; D015233:Models, Statistical; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D012307:Risk Factors