Postoperative Outcomes in Patients with Do-not-resuscitate (DNR) Orders undergoing Elective Surgery

Abstract

Background: Do-Not-Resuscitate (DNR) is a medical order against the use of cardiopulmonary resuscitation. While it does not preclude surgery, DNR status has been shown to be independently associated with worse surgical outcomes for a variety of procedures. Our prior study found that in the immediate postoperative period, DNR status was associated with increased mortality but not morbidity. This study further investigates the outcomes of DNR patients specifically in elective surgery. Understanding this relationship is crucial for informing DNR patients in goals of care discussions prior to pursuing elective surgery. Methods: Using the 2007-2015 American College of Surgeons National Surgical Quality Improvement Program database, we performed a retrospective analysis of elective surgery cases comparing DNR and non-DNR cohorts. Differences between cohorts were assessed using the Pearson chi-square test for categorical variables and Student’s t test for continuous ones. For all preoperative and operative characteristics, we applied univariate logistic regression to assess the association of each variable with DNR status. We then applied a 1:1 greedy nearest neighbor propensity score matching algorithm to reduce confounding by significant baseline characteristics and match by procedure. Lastly, we applied univariate logistic regression for all 30-day postoperative complications including mortality to assess the association of each adverse outcome with DNR status. All analyses were conducted in R Project for Statistical Computing (v3.4.0). Results: DNR patients were more likely than non-DNR patients to be older in age and have poorer preoperative state of health in terms of functional status and medical comorbidities. The most common elective surgical procedures performed in DNR patients by surgical specialty were general surgery (39%), orthopedics (20%), vascular (19%), and urology (11%); these included lower extremity amputations, Roux-en-Y gastric bypass, femur fracture repairs, carotid endarterectomy, colectomy, and cystostomy, among others. In the propensity matched cohort adjusted for preoperative and operative factors, DNR patients were found to have increased 30-day postoperative mortality (OR 2.50 [1.55-4.05], p < 0.001) and length of stay (HR 2.08 [1.31-3.30], p = 0.002). Notably, DNR patients were not found to have increased incidence of any other postoperative complications. Conclusion: DNR status is associated with higher mortality but not morbidity for elective surgeries in the 30-day postoperative period, independent of patients’ baseline health. The lack of increased postoperative complications suggests that the isolated rise in postoperative mortality may be related to inherent differences in the management of postoperative complications in patients with DNR orders. This may be a consequence of withholding resuscitative measures, failure to rescue, or transition to comfort care. Therefore, DNR patients who are considering elective surgery should thoroughly assess the risks and benefits of the procedure, along with their increased risk of mortality due to DNR status, in light of their goals of care as part of the patient-centered shared decision making process in determining the appropriateness of the elective surgery.