Performance of the pediatric index of mortality 2 (PIM-2) in cardiac and mixed intensive care units in a tertiary children’s referral hospital in Italy

BMC Pediatrics

Massimiliano Raponi²  Franco Schiavi¹  Sergio Picardo¹  Nicola Pirozzi¹  Paola Cogo³  Carla Brusco²  Silvia Rinaldi²  Lucilla Ravà⁴  Marina Cuttini⁴  Marta Luisa Ciofi degli Atti² 

[1]Department of Anesthesia and Intensive Care, Bambino Gesù Children’s Hospital, Rome, Italy

[2]Medical Direction, Bambino Gesù Children’s Hospital, Piazza S. Onofrio, 4, 00161, Rome, Italy

[3]Cardiac Surgery Intensive Care Unit, Bambino Gesù Children’s Hospital, Rome, Italy

[4]Unit of Epidemiology, Bambino Gesù Children’s Hospital, Rome, Italy

关键词: Quality indicators;    Cardiac surgery, Pediatrics;    Mortality pediatric index of mortality;    Risk adjustment;    Critical care;   

Others  :  1144699
DOI  :  10.1186/1471-2431-13-100

 received in 2012-11-09, accepted in 2013-06-20,  发布年份 2013

【 摘 要 】

Background

Mortality rate of patients admitted to Intensive Care Units is a widely adopted outcome indicator. Because of large case-mix variability, comparisons of mortality rates must be adjusted for the severity of patient illness at admission. The Pediatric Index of Mortality 2 (PIM-2) has been widely adopted as a tool for adjusting mortality rate by patients’ case mix. The objective of this study was to assess the performance of PIM-2 in children admitted to intensive care units after cardiac surgery, other surgery, or for other reasons.

Methods

This was a prospective cohort study, conducted in a 607 inpatient-bed tertiary-care pediatric hospital in Italy, with three pediatric intensive care Units (PICUs) and one cardiac Unit (CICU). In 2009–11, all consecutive admissions to PICUs/CICU of children aged 0–16 years were included in the study. Discrimination and calibration measures were computed to assess PIM-2 performance. Multivariable logistic regression analysis was used to assess the association of patients’ main reason for intensive care admission (cardiac-surgical, other-surgical, medical), age, Unit and year with observed mortality, adjusting for PIM-2 score.

Results

PIM-2 data collection was completed for 91.2% of total PICUs/CICU patient admissions (2912), and for 94.8% of patients who died in PICUs/CICU (129). Overall observed mortality was 4.4% (95% CI, 3.7-5.2), compared to 6.4% (95% CI, 5.5-7.3) expected mortality. Standardised mortality ratio was 0.7 (95% CI: 0.6-0.8). PIM-2 discrimination was fair (area under the curve, 0.79; 95% CI: 0.75-0.83). Calibration was less satisfactory, mainly because of the over two-fold overprediction of deaths in the highest risk group (114.7 vs 53; p < 0.001), and particularly in cardiac-surgical patients. Multivariable logistic analysis showed that risk of death was significantly reduced in cardiac-surgical patients and in those aged 1 month to 12 years, independently from PIM-2.

Conclusions

The children age distribution and the proportion of cardiac-surgical patients should be taken into account when interpreting SMRs estimated using the PIM-2 prediction model in different Units. A new calibration study of PIM-2 score might be needed, and more appropriate cardiac-focused risk-adjustment models should be developed. The role of age on risk of death needs to be further explored.

【 授权许可】

   
2013 Ciofi degli Atti et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

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