OBJECTIVE: Pediatric Index of Mortality 2 (PIM2) is an up-to-date mortality 
prediction model in the public domain that has not yet been widely validated. We 
aimed to evaluate this score in the population of patients admitted to our 
pediatric intensive care unit.
DESIGN: Prospective cohort study.
SETTING: Multidisciplinary pediatric intensive care unit in a general university 
hospital in Buenos Aires, Argentina.
PATIENTS: All consecutive patients admitted between January 1, 2004, and 
December 31, 2005.
INTERVENTIONS: None.
MEASUREMENTS AND MAIN RESULTS: There were 1,574 patients included in the study. 
We observed 41 (2.6%) deaths, and PIM2 estimated 48.1 (3.06) deaths. 
Discrimination assessed by the area under the receiver operating characteristic 
curve was 0.9 (95% confidence interval, 0.89-0.92). Calibration across five 
conventional mortality risk intervals assessed by the Hosmer-Lemeshow 
goodness-of-fit test showed chi5 = 12.2 (p = .0348). The standardized mortality 
ratio for the whole population was 0.85 (95% confidence interval, 0.6-1.1).
CONCLUSIONS: PIM2 showed an adequate discrimination between death and survival 
and a poor calibration assessed by the Hosmer-Lemeshow goodness-of-fit test. The 
standardized mortality ratio and clinical analysis of the Hosmer-Lemeshow table 
make us consider that PIM2 reasonably predicted the outcome of our patients.