Acute kidney injury is independently associated with mortality and resource use after emergency general surgery operations

Introduction: The incidence of severe perioperative renal dysfunction in high-acuity patients has not been well-explored at the national level. The present study aimed to evaluate the trends in the incidence of perioperative acute kidney injury and renal replacement therapy as well as associated mortality among patients undergoing an emergency general surgery operation.

Methods: This was a retrospective cohort study using the National Inpatient Sample to identify all adult patients (>18 y) without chronic kidney disease who underwent an emergency general surgery procedure from 2008 to 2016. The study cohort was stratified based on presence of acute kidney injury and need for renal replacement therapy postoperatively. A multivariable logistic regression model was developed to predict the odds of mortality and composite morbidity. Nonparametric trend analyses of acute kidney injury and renal replacement therapy incidence and associated mortality were performed.

Results: Of an estimated 5,862,657 patients who underwent an emergency general surgery procedure during the study period, 7.4% patients developed an acute kidney injury and 0.48% patients required renal replacement therapy. Overall, the incidence of acute kidney injury (5.3%-19.4%) and renal replacement therapy (0.43%-0.93%) increased (P < .0001) over the study period. Even without need for renal replacement therapy, acute kidney injury was associated with greater odds of mortality and composite morbidity (adjusted odds ratio 5.2, 95% confidence interval [CI] 5.1-5.3) and mortality (adjusted odds ratio = 2.20, 95% CI 2.3-2.4), as well as greater costs of hospitalization and duration of stay.

Conclusion: In this national study, we found that the incidence of acute kidney injury and renal replacement therapy after an emergency general surgery operation has increased. Both acute renal failure and hemodialysis were associated with much greater odds of morbidity and mortality. The apparent increase in the rate of acute kidney injury and renal replacement therapy warrant further investigation of mechanisms for monitoring and limiting the impact of organ malperfusion associated with emergency general surgery operations.