PURPOSE:The Standardized Mortality Ratio (SMR) has been used as a measure of clinical performance in the intensive care units (ICUs). When using APACHE II scoring system; a value of less than one is expected to reflect the advancement in ICU practice and improved mortality over the past 20 years. The objective of our study is to determine the APACHE II SMR value of our patients in comparison with the APACHE IV SMR.
METHODS:In a prospective cohort study, we determined the severity of disease of patients who were admitted to our ICU between January 1, 2007 to February 29, 2008 using APACHE II, and APACHE IV scoring systems. Patients were divided into 4 groups with increasing severity of illness (intervals of 15's in APACHE II and 50's in APACHE IV), the actual and predicted mortalities for each group was used to calculate the SMRs. The results were compared between APACHE II and APACHE IV.
RESULTS:Total of 1689 patients were admitted to the ICU during the study period. We included 1575 ICU admissions representing 1362 hospital admissions with an average age of 48.3 years. 53% (n=718) of patients were men, 51% were post surgical, 18% from general wards, and 21% from emergency room. We obtained actual mortality of 18.8% with average APACHE II of 17.5, predicted mortality of 30.8% and SMR of 0.61 compared to average APACHE IV of 57.2, predicted mortality of 19.2% and SMR of 0.98. The tendencies of SMRs using APACHE II, and APACHE IV among the 4 groups were consistent with increasing severity of illness except in the highest severity group (P > 0.05).
CONCLUSION:When comparing SMRs of both APACHE II and APACHE IV systems, it is determined that APACHE II SMR of around 0.6 represents a value that reflects the advancements in clinical practice.
CLINICAL IMPLICATIONS:Hospitals that are still using APACHE II system can utilize the results of this study for benchmarking.
DISCLOSURE:Mazen Kherallah, No Financial Disclosure Information; No Product/Research Disclosure Information