Abstract Prognostic scores such as the Pediatric Index of Mortality (PIM-3) are widely used to estimate mortality risk in PICUs, yet their performance in low- and middle-income countries (LMICs) remains uncertain. We aimed to evaluate the predictive performance of PIM-3 in a Moroccan PICU; associations with ICU length of stay (LOS) and duration of mechanical ventilation (MV) were secondary exploratory outcomes. We conducted a prospective cohort study in the Mother–Child PICU at Hassan II University Hospital (Fez, Morocco) from June 1 to September 30, 2024, including all children aged 1 month to 16 years. PIM-3 variables were collected at admission. The primary focus was model performance: discrimination (AUROC, AUPRC), calibration (Hosmer–Lemeshow), and standardized mortality ratio (SMR). Univariable and multivariable regressions were used for the secondary exploratory analyses (mortality correlates, LOS, and MV duration). Among 122 patients, observed mortality was 28.7%, exceeding PIM-3 predictions (SMR = 7.7; p < 0.001). PIM-3 showed good discrimination (AUROC = 0.86; AUPRC = 0.65) but poor calibration. In secondary exploratory analyses, higher PIM-3 scores, lower GCS, multiple organ failures, and need for MV were associated with mortality. MV increased ICU stay duration and organ failures prolonged ventilation duration. Conclusion: In this Moroccan PICU, PIM-3 showed good discrimination but poor calibration and thus underestimated mortality. These findings support considering local recalibration in future work, and exploration of machine-learning–based adaptation for LMIC settings.  Clinical trial number: Not applicable.<Table Float="No" ID="Taba"> <tgroup cols="2"> <colspec align="left" colname="c1" colnum="1" /> <colspec align="left" colname="c2" colnum="2" /> <tbody> <row> <entry align="left" nameend="c2" namest="c1"> What is Known: • PIM-3 is widely used to estimate PICU mortality risk. It was developed and calibrated largely in high-resource settings. • External validations often show good discrimination but variable calibration, with under- or over-estimation in LMICs due to differences in case-mix, care processes, and resources. What is New: • In a prospective Moroccan PICU cohort (n=122), PIM-3 showed good discrimination (AUROC 0.86; AUPRC 0.65) but markedly underestimated mortality (SMR 7.7). • Higher PIM-3 risk, lower Glasgow Coma Scale, multiple organ failures, and mechanical ventilation were associated with death, underscoring the need for local recalibration and exploration of machine learning-based adaptations for LMICs. </entry> </row> </tbody> </tgroup> </Table>

Performance of the pediatric index of mortality (PIM-3) in a Moroccan PICU: challenges in resource-limited settings

期刊论文
发表日期：

2025年11月15日

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Imad Daoudi,
Djoudline Doughmi,
Said Benlamkaddem,
Adnane Berdai,
Mustapha Harandou

摘要

Abstract

Prognostic scores such as the Pediatric Index of Mortality (PIM-3) are widely used to estimate mortality risk in PICUs, yet their performance in low- and middle-income countries (LMICs) remains uncertain. We aimed to evaluate the predictive performance of PIM-3 in a Moroccan PICU; associations with ICU length of stay (LOS) and duration of mechanical ventilation (MV) were secondary exploratory outcomes. We conducted a prospective cohort study in the Mother–Child PICU at Hassan II University Hospital (Fez, Morocco) from June 1 to September 30, 2024, including all children aged 1 month to 16 years. PIM-3 variables were collected at admission. The primary focus was model performance: discrimination (AUROC, AUPRC), calibration (Hosmer–Lemeshow), and standardized mortality ratio (SMR). Univariable and multivariable regressions were used for the secondary exploratory analyses (mortality correlates, LOS, and MV duration). Among 122 patients, observed mortality was 28.7%, exceeding PIM-3 predictions (SMR = 7.7; p < 0.001). PIM-3 showed good discrimination (AUROC = 0.86; AUPRC = 0.65) but poor calibration. In secondary exploratory analyses, higher PIM-3 scores, lower GCS, multiple organ failures, and need for MV were associated with mortality. MV increased ICU stay duration and organ failures prolonged ventilation duration.

Conclusion: In this Moroccan PICU, PIM-3 showed good discrimination but poor calibration and thus underestimated mortality. These findings support considering local recalibration in future work, and exploration of machine-learning–based adaptation for LMIC settings.

Clinical trial number: Not applicable.

What is Known:

• PIM-3 is widely used to estimate PICU mortality risk. It was developed and calibrated largely in high-resource settings.

• External validations often show good discrimination but variable calibration, with under- or over-estimation in LMICs due to differences in case-mix, care processes, and resources.

What is New:

• In a prospective Moroccan PICU cohort (n=122), PIM-3 showed good discrimination (AUROC 0.86; AUPRC 0.65) but markedly underestimated mortality (SMR 7.7).

• Higher PIM-3 risk, lower Glasgow Coma Scale, multiple organ failures, and mechanical ventilation were associated with death, underscoring the need for local recalibration and exploration of machine learning-based adaptations for LMICs.