title: Comparison of cumulative incidence analysis and Kaplan-Meier for analysis of shock reversal in patients with septic shock.
abstract: BACKGROUND
  Kaplan-Meier (KM) has become the most used method to evaluate time-to-event analysis, although it is unsuitable in competing event situations such as death and shock reversal. Despite that the use of this methodology is not widely disseminated, cumulative incidence analysis (CIA) is more appropriate in these situations. We used CIA and KM (with 2 different techniques of censoring) to compare shock reversal in a cohort of patients with septic shock after steroid therapy. Furthermore, we have analyzed shock reversal in responders and nonresponders to high-dose cortrosyn test (250 μg).
  
  
  METHODS
  Analysis of shock reversal in a cohort of 74 patients with septic shock at a university hospital was done.
  
  
  RESULTS
  Shock reversal by the 28th day was estimated to be 88% and 72% by KM methods and 59% by CIA. In nonresponders to cortrosyn test (Δ ≤ 9 μg/dL), shock reversal was estimated in 80% and 56% according to KM and 47% according to CIA. As for responders to cortrosyn test, shock reversal was estimated in 90% and 77% according to KM and 64% according to the CIA method.
  
  
  CONCLUSIONS
  Kaplan-Meier overestimates shock reversal. Cumulative incidence analysis seems to be a more appropriate method to analyze shock reversal. Future trials intended to analyze shock reversal should apply CIA.
authors.affiliation: Department of Critical Care Medicine, Hospital de Clínicas de Porto Alegre, 90830-000 Porto Alegre, RS, Brazil. moraesrb@hotmail.com
authors.forename: Rafael Barberena
authors.initials: RB
authors.lastname: Moraes
authors.forename: Gilberto
authors.initials: G
authors.lastname: Friedman
authors.forename: Thiago
authors.initials: T
authors.lastname: Lisboa
authors.forename: Marina Verçoza
authors.initials: MV
authors.lastname: Viana
authors.forename: Vânia
authors.initials: V
authors.lastname: Hirakata
authors.forename: Mauro A
authors.initials: MA
authors.lastname: Czepielewski
mesh_terms: D000305:Adrenal Cortex Hormones / Q000097:blood / Q000627:therapeutic use*; D004341:Drug Evaluation / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D012772:Shock, Septic / Q000175:diagnosis / Q000188:drug therapy* / Q000401:mortality; D016019:Survival Analysis
chemical_list: D000305:Adrenal Cortex Hormones