Figure 2. Surgical 90-Day Mortality According to Risk Group Score in the Development and Validation Cohorts.

The best cutoff was reached to collapse the cohort into 5 different homogeneous groups of risk according to their score: very low risk (score, ≥1), low risk (score, 0), medium risk (score, −1 to −2), high risk (score, −3 to −4), and very high risk (score, ≤−5).