Impact of Chronic Immunosuppression on Emergency General Surgery Outcomes

BACKGROUND: Although patients on immunosuppressive agents are at increased risk for complications after surgery, the impact of immunosuppressive medications on surgical outcomes in the emergency setting remains unclear. As the number of people on chronic immunosuppression rises, this cohort may disproportionately contribute to outcomes associated with emergency general surgery (EGS). STUDY DESIGN: We evaluated patients from a statewide EGS collaborative undergoing the following operations: cholecystectomy, appendectomy, operation for small-bowel obstruction, or emergent exploratory laparotomy. The exposure was preexisting chronic usage of corticosteroid or immunosuppressive agents. Risk-adjusted outcomes were evaluated using entropy balancing, a technique that reweights control covariates to ensure reproducible balance between the exposure and control populations without losing data. The primary outcome was mortality, and secondary outcomes included complications, readmission, and discharge disposition. We performed a sensitivity analysis with propensity score matching. RESULTS: We identified 30,073 adult patients, of whom 1,538 (5.1%) were on chronic immunosuppression. In the overall cohort, immunosuppressive medication use was associated with higher rates of mortality (marginal effect 2.3, 95% CI 1.0 to 3.6, p < 0.001), complications, infection, sepsis, and readmission. Sensitivity analysis yielded similar results. In subgroup analysis by operation, only emergent exploratory laparotomy had a higher rate of mortality associated with immunosuppression use. No association between immunosuppressive medication use and mortality was found following appendectomy, cholecystectomy, or surgery for small-bowel obstruction. CONCLUSIONS: Patients on chronic immunosuppressive medication constitute a substantial portion of the EGS population. Mortality rates are worse for larger operations, such as exploratory laparotomy, in this population. Less complicated operations such as cholecystectomy and appendectomy can be performed safely without increased risk of mortality in this population, despite a modest increase in nonfatal complications.