competing risk of death

Competing risk is when another unrelated variable affects your primary outcome. If the primary outcome is mortality, the variable competes with your intervention. For example, if you are studying the effect of chemotherapy on mortality for breast cancer, and a patient dies from heart attack, heart attack is a competing risk of death for chemotherapy. The patient cannot die from both.

Competing risk of death is important in ICU because most studies have mortality as one of the end points, and patients can die from a lot of things in the ICU. Furthermore, intervention that increases mortality will decrease length of stay.