Objective: The objectives are to explore the characteristics of organ failure and support in the medical intensive care units and exam the effect of organ failure on mortality.

Material and methods: This was a prospective cohort studyof critically ill medical patients. All consecutive patients were collected for one year. Demographic data, organ failure characteristics, and support were recorded. Outcomes were mortality at day 28, 90, and year one.

Results: A total of 446 patients were included. The median age was 60 years (IQR 46, 73), and the male was 58.3%. Median Charlson comorbidities index was 4 points (IQR 2, 4). Median APACHE II and SOFA scores were 23 (IQR 18, 30) and 8 points (IQR 5, 11). ARF developed 69.1% (95%CI 61.7-70.2). Mechanical ventilation duration was 6 days (95%CI 4-6), whereas the ventilator-free day on day 28 was 22 days (95%CI 16-23). Ventilator associated pneumonia rate was 9.4 events per 1000 ventilator-days (95%CI 6.1-13.8). AKI developed 71.5% (95%CI 66.8-75.7): 25.2%, 20.5%, and 54.3% had stage I, II, III AKI. Patients developed shock 66.8%. Septic shock was the most common type. The median time to start nutrition support was 1 day (IQR 1.0, 2.0). Mortality at day 28, day 90, and 1 year were 30.7% (95%CI   26.6-35.1), 42.4% (95%CI 37.9-47), and 53.8% (95%CI 49.2-58.4). ARF had a constant effect on death at day 28 (HR 3.68, 95%CI 1.96-6.91). Shock had a peak effect on mortality since day 1 of ICU admission (HR 120.3, 95%CI 4.76-3040.7) and still had a significant impact on day 28 (HR 2.07, 95%CI 1.14-3.74). Development of stage III AKI had an earlier effect than stage II AKI on mortality and a peak effect at day 28.

Conclusion: AKI and ARF were common in ICU. Shock had the highest effect on mortality, followed by ARF and AKI.

Key words: organ failure, medical critically ill patients, intensive care unit, mortality, epidemiology.