title: Comparison between SAPS II and SAPS 3 in predicting hospital mortality in a cohort of 103 Italian ICUs. Is new always better?
abstract: OBJECTIVE
  More recent severity scores should be more reliable than older ones because they account for the improvement in medical care over time. To provide more insight into this issue, we compared the predictive ability of the Simplified Acute Physiology Score (SAPS) II and SAPS 3 (originally developed from data collected in 1991-1992 and 2002, respectively) on a sample of critically ill patients.
  
  
  METHODS
  This was a prospective observational study on 3,661 patients from 103 Italian intensive care units. Standardized mortality ratios (SMRs) were calculated. Assessment of calibration across risk classes was performed using the GiViTI calibration belt. Discrimination was evaluated by means of the area under the receiver operating characteristic analysis.
  
  
  RESULTS
  Both scores were shown to discriminate fairly. SAPS 3 largely overpredicted mortality, more than SAPS II (SMR 0.63, 95 % CI 0.60-0.66 vs. 0.87, 95 % CI 0.83-0.91). This result was consistent and statistically significant across all risk classes for SAPS 3. SAPS II did not show relevant deviations from ideal calibration in the first two deciles of risk, whereas in higher-risk classes it overpredicted mortality.
  
  
  CONCLUSIONS
  Both scores provided unreliable predictions, but unexpectedly the newer SAPS 3 turned out to overpredict mortality more than the older SAPS II.
authors.affiliation: Servizio Anestesia e Rianimazione, Ospedale Civile San Martino, Belluno, Italy. daniele.poole@alice.it
authors.forename: Daniele
authors.initials: D
authors.lastname: Poole
authors.forename: Carlotta
authors.initials: C
authors.lastname: Rossi
authors.forename: Nicola
authors.initials: N
authors.lastname: Latronico
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Rossi
authors.forename: Stefano
authors.initials: S
authors.lastname: Finazzi
authors.forename: Guido
authors.initials: G
authors.lastname: Bertolini
mesh_terms: D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units; D007558:Italy; D017063:Outcome Assessment, Health Care / Q000379:methods; D011446:Prospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index