APACHE IV: benchmarking in an Indian ICU

Comparison of APACHE II and APACHE IV score as predictors of mortality in patients with septic shock in intensive care unit: A prospective observational study

Background and Aims

Prediction of outcome in intensive care unit (ICU) patients is of imperative importance. Our aim was to assess and compare the performance of Acute Physiology and Chronic Health Evaluation (APACHE) II and APACHE IV scores in predicting mortality in adult patients suffering from septic shock admitted to our ICU.

Material and Methods

This was a prospective observational study conducted in a 14-bedded medical ICU of a tertiary care center from January 2019 to March 2020; 128 patients suffering from septic shock were included and APACHE II and IV scores were calculated. We also calculated the predicted and actual mortality rates and standardized mortality ratios. The receiver operating characteristic curves were used to assess discrimination.

Results

Out of the 128 patients, 63 patients (49.21%) died. The mean (± standard deviation) admission APACHE II score was 16.7 ± 5.53, while the mean APACHE IV score was 67.25 ± 25.99. The non-survivors had significantly higher APACHE II and IV scores when compared to those who survived (P < 0.001). APACHE II had a slightly better discriminative power (with the area under the Receiver operating characteristic (ROC) curve of 0.78) than APACHE IV (with the area under the ROC curve of 0.74). The mean predicted mortality rate (PMR) of the patient population calculated on the basis of the APACHE II scoring system was 22.46 ± 15.76, and the mean PMR calculated as per the APACHE IV scoring system was 11.64 ± 15.59.

Conclusion

Both APACHE II and APACHE IV underestimated mortality in septic shock patients. Both APACHE II and APACHE IV were comparable in differentiating survivors from non-survivors. However, there was a good correlation between the two models.

Characteristics and outcomes of patients admitted to adult intensive care units in Hong Kong: a population retrospective cohort study from 2008 to 2018

Background

Globally, mortality rates of patients admitted to the intensive care unit (ICU) have decreased over the last two decades. However, evaluations of the temporal trends in the characteristics and outcomes of ICU patients in Asia are limited. The objective of this study was to describe the characteristics and risk adjusted outcomes of all patients admitted to publicly funded ICUs in Hong Kong over a 11-year period. The secondary objective was to validate the predictive performance of Acute Physiology And Chronic Health Evaluation (APACHE) IV for ICU patients in Hong Kong.

Methods

This was an 11-year population-based retrospective study of all patients admitted to adult general (mixed medical-surgical) intensive care units in Hong Kong public hospitals. ICU patients were identified from a population electronic health record database. Prospectively collected APACHE IV data and clinical outcomes were analysed.

Results

From 1 April 2008 to 31 March 2019, there were a total of 133,858 adult ICU admissions in Hong Kong public hospitals. During this time, annual ICU admissions increased from 11,267 to 14,068, whilst hospital mortality decreased from 19.7 to 14.3%. The APACHE IV standard mortality ratio (SMR) decreased from 0.81 to 0.65 during the same period. Linear regression demonstrated that APACHE IV SMR changed by − 0.15 (95% CI − 0.18 to − 0.11) per year (Pearson’s R = − 0.951, p < 0.001). Observed median ICU length of stay was shorter than that predicted by APACHE IV (1.98 vs. 4.77, p < 0.001). C-statistic for APACHE IV to predict hospital mortality was 0.889 (95% CI 0.887 to 0.891) whilst calibration was limited (Hosmer–Lemeshow test p < 0.001).

Conclusions

Despite relatively modest per capita health expenditure, and a small number of ICU beds per population, Hong Kong consistently provides a high-quality and efficient ICU service. Number of adult ICU admissions has increased, whilst adjusted mortality has decreased over the last decade. Although APACHE IV had good discrimination for hospital mortality, it overestimated hospital mortality of critically ill patients in Hong Kong.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-020-00513-9.

The Ability of the Acute Physiology and Chronic Health Evaluation (APACHE) IV Score to Predict Mortality in a Single Tertiary Hospital

Background

The Acute Physiology and Chronic Health Evaluation (APACHE) II model has been widely used in Korea. However, there have been few studies on the APACHE IV model in Korean intensive care units (ICUs). The aim of this study was to compare the ability of APACHE IV and APACHE II in predicting hospital mortality, and to investigate the ability of APACHE IV as a critical care triage criterion.

Methods

The study was designed as a prospective cohort study. Measurements of discrimination and calibration were performed using the area under the receiver operating characteristic curve (AUROC) and the Hosmer-Lemeshow goodness-of-fit test respectively. We also calculated the standardized mortality ratio (SMR).

Results

The APACHE IV score, the Charlson Comorbidity index (CCI) score, acute respiratory distress syndrome, and unplanned ICU admissions were independently associated with hospital mortality. The calibration, discrimination, and SMR of APACHE IV were good (H = 7.67, P = 0.465; C = 3.42, P = 0.905; AUROC = 0.759; SMR = 1.00). However, the explanatory power of an APACHE IV score >93 alone on hospital mortality was low at 44.1%. The explanatory power was increased to 53.8% when the hospital mortality was predicted using a model that considers APACHE IV >93 scores, medical admission, and risk factors for CCI >3 coincidentally. However, the discriminative ability of the prediction model was unsatisfactory (C index <0.70).

Conclusions

The APACHE IV presented good discrimination, calibration, and SMR for hospital mortality.