Mortality prediction using SAPS II: an update for French intensive care units.

INTRODUCTION: The standardized mortality ratio (SMR) is commonly used for benchmarking intensive care units (ICUs). Available mortality prediction models are outdated and must be adapted to current populations of interest. The objective of this study was to improve the Simplified Acute Physiology Score (SAPS) II for mortality prediction in ICUs, thereby improving SMR estimates. METHOD: A retrospective data base study was conducted in patients hospitalized in 106 French ICUs between 1 January 1998 and 31 December 1999. A total of 77,490 evaluable admissions were split into a training set and a validation set. Calibration and discrimination were determined for the original SAPS II, a customized SAPS II and an expanded SAPS II developed in the training set by adding six admission variables: age, sex, length of pre-ICU hospital stay, patient location before ICU, clinical category and whether drug overdose was present. The training set was used for internal validation and the validation set for external validation. RESULTS: With the original SAPS II calibration was poor, with marked underestimation of observed mortality, whereas discrimination was good (area under the receiver operating characteristic curve 0.858). Customization improved calibration but had poor uniformity of fit; discrimination was unchanged. The expanded SAPS II exhibited good calibration, good uniformity of fit and better discrimination (area under the receiver operating characteristic curve 0.879). The SMR in the validation set was 1.007 (confidence interval 0.985-1.028). Some ICUs had better and others worse performance with the expanded SAPS II than with the customized SAPS II. CONCLUSION: The original SAPS II model did not perform sufficiently well to be useful for benchmarking in France. Customization improved the statistical qualities of the model but gave poor uniformity of fit. Adding simple variables to create an expanded SAPS II model led to better calibration, discrimination and uniformity of fit, producing a tool suitable for benchmarking.

The variation of serum cortisol during ovarian stimulation for in vitro fertilization.

AIM: As there is no consensus concerning the variation of serum cortisol level during in vitro fertilization (IVF), we studied it prospectively by frequent evaluation throughout the course of an IVF cycle and compared the value, as control, of cortisol concentration obtained in the previous month (M-1) with the concentration obtained on the first day (D1) of ovarian stimulation. METHODS: In 23 IVF cycles using gonadotropin-releasing hormone agonist/human menopausal gonadotropins (hMG)/human chorionic gonadotropin, cortisol and estradiol were measured at M-1, D1, day 14 (D14, before beginning hMG), day 16 (D16), day 19 (D19), day 22 (D22), day 24 (D24), the day before (T-1) and the day after triggering ovulation (T+1), the day of oocyte retrieval (OR), 15 days after embryo transfer (ET+15) and the next month (M2). Statistical analysis used tests of linear tendency, the Pearson chi(2) test, analysis of variance, Student's t test and Spearman correlation. RESULTS: Cortisol was non-significantly lower at M-1 compared with D1; although remaining in the normal range, mean cortisol increased progressively after D1, in a manner unrelated to estradiol, with non-significant differences between different time points but a significant linear tendency and a maximum value at T+1. All mean cortisol values were significantly higher than that at M-1 and, except for D19 and T-1, D1. Mean cortisol decreased at ET+15 and significantly at M2, the value at M2 being lower than that at M-1. CONCLUSION: Cortisol showed a progressive increase beginning from D1, especially after ovulation triggering, and returned to pre-treatment level next month. Cortisol variation was not related to the changes in the E(2) values. Cortisol values at both M-1 and D1 could be used as controls.