Introduction:
The aim of this study was to evaluate intensive care unit (ICU) performance using risk-adjusted ICU mortality rates nationally, assessing patients who died or had been discharged from the ICU. For this purpose, this study analyzed the Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) databases, containing detailed clinical and physiological information and mortality of mixed critically ill patients in a medical ICU at secondary and tertiary referral ICUs in Turkey.

Material and methods:
A total of 690 adult intensive care units in Turkey were included in the study. Among 690 ICUs evaluated, 39.7% were secondary and 60.3% were tertiary ICUs. A total of 4188 patients were enrolled in this study. Intensive care units of ministry, university, and private hospitals were evaluated all over Turkey. During the study period, clinical data that were collected concurrently for each patient contained demographic details and the diagnostic category leading to ICU admission. APACHE II and SOFA scores following ICU admission were calculated and recorded. Patients were followed up for outcome data until death or ICU discharge.

Results:
The mean age of patients was 68.8 ±19 and 54% of them were male. The mean APACHE II score was 20 ±8.7. The ICUs’ mortality rate was 46.3%, and mean predicted mortality was 37.2% for APACHE II. The standardized mortality ratio was 1.28 (95% confidence interval: 1.21–1.31).

Conclusions:
There was a wide difference in outcome for patients admitted to different ICUs and severity of illness using risk adjustment methods. The high mortality rate in patients could be related to comorbid diseases, high mechanical ventilation rates and older ages.