9% of patients with CCCs, may be secondary to differences in the characteristics between the study samples and those used in the score development. Murphy-Filkins et al. reported that changes in the demographic characteristics of patients and in the prevalence of diseases alter the mix of cases, which may influence score performance.20 Perhaps, with the recently observed increase in the prevalence of CCCs among patients admitted to the PICU and the observation that these patients have a higher mortality rate than the general population, it will be necessary that future scores for outcome prediction use this condition when their models are being constructed. The

SMR of 1.65 TGF-beta inhibitor (95% CI: 1.26 to 2.04) for the general population and of 1.75 (95% CI: 1.31 to 2.19) for the subgroup of

patients with CCCs indicated that the quality of health care offered at the PICU for these patients during the study period was worse than the quality of health care offered by the PICUs that participated in the PIM2 development study in the period between 1997 and 1999. However, the SMR of 1.14 (0.29 to 1.99) for patients without CCCs indicated that the quality of health care offered at the PICU for this subgroup in the study period was similar to the quality of health care offered by the PICUs that participated in PIM2 development study between 1997 and Buparlisib price 1999. The SMR is the main indicator of health care quality in the PICU, and is part of the first set of quality indicators that were submitted to the Joint Commission on Accreditation of Healthcare Organizations, published in 2005.21 However, the accuracy of this indicator depends on the capacity of the score in predicting mortality in the studied population;8 thus, in addition

to the hypothesis of inadequate quality as the cause of the high SMR in the overall study population and in the subgroup of patients with CCCs, the hypothesis that the PIM2 Reverse transcriptase may not be adequate for the studied population cannot be ruled out. This study has some limitations. The principal limitation is the fact that the study was conducted in a single PICU, making it difficult to prove the hypothesis and subsequently, the generalizability of the findings. Operating conditions (equipment, medications, and staff) in the studied PICU may not be similar to those of PICUs in developed countries, which may have influenced the results. Finally, the statistical analysis may have been influenced by the relatively small sample size. The PIM2 showed poor performance in the subgroup of patients with CCCs and the overall study population, which had 83.9% of patients with CCCs. Although the poor performance of the score may be secondary to the quality of health care offered by the PICU, the hypothesis that the difference in characteristics between the study sample and the sample used for the score development is responsible for inadequate performance of PIM2 cannot be ruled out.