PURPOSE:Evaluation of the performance of the APACHE (acute physiology and chronic health evaluation) IV at a Saudi tertiary adult intensive care unit (ICU).
METHODS:Prospective study for all ICU patients who were admitted in 14 month period. Outcome was survival status on discharge from the hospital. Comparisons were made between the APACHE IV developmental patient sample and our patients using t test with P <0.05. The agreement between predicted and observed mortality rates in risk ranges was assessed using calibration curves with 10 equal, contiguous risk ranges that represent observed against predicted outcomes with 95% confidence intervals and p < 0.05. Discrimination was assessed by calculating area under the Receiver Operating Characteristic (ROC) curves, with estimates of the standard error and confidence intervals.
RESULTS:Total of 1580 patients were included with average APACHE IV score of 58.7 and acute physiology score (APS) component of 47.8 that appeared higher for our hospital compared to the sample database. The observed hospital mortality rate (19.1%) was significantly higher than the sample database mortality rate of 13.6% [p < 0.05] and was slightly lower than predicted mortality rate of 19.5% [p >0.05]. The mean length of stay in ICU was 8.1 days (median 3). The observed mortality rate for medical patients was slightly higher than predicted mortality rate with no statistical significance, whereas for postoperative patients it was significantly lower than the predicted mortality rate [p= 0.0001]. The hospital mortality calibration curve show good calibration with line of perfect fit and agreement lying within the 95% confidence intervals for all risk ranges. P values of less than 0.05 confirm adequate calibration. Although calibration curve show that observed mortality differs from expected in the 60–70% and 80- 90% ranges; there is no statistical significance for its deviations from perfect fit. Receiver operating characteristic curve area for hospital mortality (0.81) demonstrated very good discrimination.
CONCLUSION:APACHE VI system performs acceptably in our population.
CLINICAL IMPLICATIONS:APACHE IV system can be utilized in Saudi if validated in other settings.
DISCLOSURE:Mazen Kherallah, No Financial Disclosure Information; No Product/Research Disclosure Information