Department of Pediatrics, Kwong Wah Hospital, Hong Kong, China.
Indian J Pediatr. 2011 Dec;78(12):1491-4. doi: 10.1007/s12098-011-0443-8. Epub 2011 May 27.
To compare the probabilities of death predicted by Pediatric Index of Mortality 2 (PIM2) and Pediatric Index of Mortality 1 (PIM1) models against actual mortalities in 3 pediatric intensive care units in Hong Kong.
All consecutive patients admitted to pediatric intensive care units in 3 regional non-teaching hospitals between Jan 2006 and December 2006 were included. The data required for PIM1 and PIM2 were collected. The probabilities of death predicted by PIM1 and PIM2 were validated against the actual probability of mortality.
Of the 540 patients were included in this study, only seven deaths were observed (1.3%). PIM 1 and PIM 2 overestimated the mortality rate by giving a greater mortality rate. (PIM1: 13.4, Standardized mortality ratio = 0.52, 95% CI = 0.14 to 0.91; PIM2: 14.2, Standardized mortality ratio =0.49, 95% CI = 0.13 to 0.86) The discrimination of PIM1 and PIM2 were satisfactory as reflected by area under receiver-operator characteristic curve of 0.889 (95% CI: 0.703 to 1.000) and 0.904 (95% CI: 0.738 to 1.000) respectively. Calibration was not possible due to insufficient death cases.
The current study showed that PIM2 and PIM1 had similar accuracy in mortality prediction in Hong Kong. The current study also demonstrated the difficulty to calibrate the mortality model when actual mortality rate is low.
比较香港 3 家儿科重症监护病房使用儿科死亡率指数 2 （PIM2）和儿科死亡率指数 1 （PIM1）模型预测死亡率与实际死亡率的差异。
纳入 2006 年 1 月至 2006 年 12 月期间在 3 家地区非教学医院的儿科重症监护病房连续收治的所有患者。收集 PIM1 和 PIM2 所需的数据。验证 PIM1 和 PIM2 预测的死亡概率与实际死亡率的吻合程度。
本研究共纳入 540 例患者，仅观察到 7 例死亡（1.3%）。PIM1 和 PIM2 高估了死亡率，预测死亡率更高。（PIM1：13.4，标准化死亡率比=0.52，95%可信区间=0.14 至 0.91；PIM2：14.2，标准化死亡率比=0.49，95%可信区间=0.13 至 0.86）。PIM1 和 PIM2 的区分度均令人满意，ROC 曲线下面积分别为 0.889（95%可信区间：0.703 至 1.000）和 0.904（95%可信区间：0.738 至 1.000）。由于死亡病例不足，无法进行校准。
本研究表明 PIM2 和 PIM1 在香港的死亡率预测中具有相似的准确性。本研究还表明，当实际死亡率较低时，死亡率模型的校准存在困难。
