Validity of Pediatric Index of Mortality 2 score as an Outcome Predictor in Pediatric ICU of a Public Sector Tertiary Care Hospital in Pakistan

Abstract

Pediatric Index of Mortality 2 (PIM-2) is one of the leading mortality scores used in intensive care units all around the world. We assessed its validity as an outcome predictor in a pediatric intensive care unit (PICU) of Mayo Hospital/King Edward Medical University Lahore, Pakistan. We enrolled 154 consecutive admissions, aged 1 month to 13 years, requiring intensive care from January to June of 2019. Patient demographics along with PIM-2 data were collected; PIM-2 score and mortality risk was calculated; and the outcome recorded as death or survival. The median age at admission was 0.50 years (interquartile range [IQR]: 0.24–1.78) and the median weight was 5.0 kg (IQR: 3.08–10.0) with females constituting 54%; malnutrition was also common (66%). Observed mortality was 29.9% (46 out of 154) and expected mortality (cut-off ≥ 99.8%) was 27.9% with a standardized mortality ratio of 1.07 (95% confidence interval [CI]: 0.79–1.41). Sepsis was the most common diagnosis at admission (27.9%) with the highest mortality (52.2%). Chi-square analysis revealed a sensitivity of 54.3% and a specificity of 83.3% (p-value 0.00). PIM-2 score showed acceptable discrimination between survivors and nonsurvivors with an area under the receiver operating characteristic curve of 0.75 (95% CI: 0.67–0.84) (p-value = 0.00); however, poor calibration according to Hosmer–Lemeshow goodness of fit test (Chi-square = 15.80, df = 7, and p-value of 0.027 [< 0.1]), thus requiring recalibration according to local population characteristics.

A Retrospective Study on the Availability of Arterial Lactate Levels as a Biomarker of Mortality in Critically Ill Children

“…In a previous study, the combined assessment of PRISM-III scores and lactate levels during hospitalization was shown to better in predicting mortality (p=0.018) (21). In another study, lactate level during hospitalization was shown to predict mortality independently of PIM-2 scores in patients admitted to the PICU (10). In their study in patients with sepsis, Scott et al showed that the median lactate level obtained from venous catheters was 2.26 (IQR: 1.76-3.63) mmol/L in patients with a PELOD score ≥10 and 2.02 (IQR: 1.44-2.83) in patients with a PELOD score <10 (34).…”

“…On the other hand, there are also studies showing that the initial lactate level measured at the time of hospitalization is a poor predictor of mortality. Mortality studies with a single lactate value at the time of hospitalization as well as studies with serial lactate measurements are still controversial (10,22,27).…”

“…The results of both serial lactate measurements and studies predicting mortality with a single lactate measurement taken during hospitalization are limited and controversial. Furthermore, a cut-off limit of lactate for predicting the risk of death in critically ill children has not been established (9,10).…”