A nationwide Danish register cohort followed all 61,400 adults who had major emergency abdominal surgery between 2002 and 2022, measuring mortality at 7, 90 and 365 days. Liver disease had the strongest association with death within seven days (OR 2.75), while metastatic malignant disease dominated later mortality (OR 9.37 between 91 and 365 days). Regression identified combinations involving cardiac, renal, liver and cerebrovascular disease whose joint association with death exceeded the sum of the separate associations.
Why it is interesting: It tests the assumption of independence between conditions that underlies the comorbidity indices used throughout risk stratification.