Long-term mortality after critical care: what is the starting point?

Mortality is still the most assessed outcome in the critically ill patient and is routinely used as the primary end-point in intervention trials, cohort studies, and benchmarking analysis. Despite this, interest in patient-centered prognosis after ICU discharge is increasing, and several studies report quality of life and long-term outcomes after critical illness. In a recent issue of Critical Care, Cuthbertson and colleagues reported interesting results from a cohort of 439 patients with sepsis, who showed high ongoing long-term mortality rates after severe sepsis, reaching 61% at 5 years (from a starting point of ICU admission). Follow-up may start at ICU admission, after ICU discharge, or after hospital discharge. Using ICU admission as a starting point will include patients with a wide range of illness severities and reasons for ICU admission. As a result, important consequences of the ICU, such as rehabilitation and reduced quality of life, may be diluted in an unselected population. ICU discharge is another frequently used starting point. ICU discharge is a marker of better outcome and reduced risk for acute deterioration, making this an interesting starting point for studying long-term mortality, need for ICU readmission, and critical illness rehabilitation. Finally, using hospital discharge as the starting point will include patients with the minimal requirements to sustain an adequate condition in a non-monitored environment but will add a ?survivors bias?; that is, patients who survive critical illness are a special group among the critically ill. In this commentary, we discuss the heterogeneity in long-term mortality from recent studies in critical care medicine ? heterogeneity that may be a consequence simply of changing the follow-up starting point ? and propose a standardized follow-up starting point for future studies according to the outcome of interest.