Systemic lupus erythematosus is associated with increased adverse postoperative renal outcomes and mortality: A historical cohort study using administrative health data

Background: Systemic lupus erythematosus (SLE) is a common autoimmune connective tissue disease that mainly harms kidneys, heart, lungs, and nervous system. Effects of surgical stimulus and anesthesia combined with SLE-related pathologies may increase morbidity and mortality. Therefore, we aimed to evaluate the association between SLE (versus none) and postoperative renal, cardiac, and in-hospital mortality complications among patients undergoing major surgeries. Methods: We obtained censuses of 2009 to 2011 inpatient hospital discharges across 7 states and conducted a retrospective cohort study by using International Classification of Diseases and Injuries, Version 9, diagnosis codes, procedure codes, and present-on-admission indicators. We included patients who had major surgery and matched each SLE discharge up to 4 control discharges for potential confounders. We assessed the association between matched SLE patients and controls on in-hospital renal complications, cardiovascular complications, and in-hospital mortality using separate logistic regression models. Results: Among 8 million qualifying discharges, our sample contained 28,269 SLE patients matched with 13,269 controls. SLE was associated with a significantly higher risk of postoperative renal complications, with an estimated odds ratio (99% CI) of 1.33 (1.21, 1.46); P < .001. In addition, SLE was significantly associated with a higher risk of in-hospital mortality, with an estimated odds ratio (99% CI) of 1.27 (1.11, 1.47); P < .001. However, we found no significant association between SLE and cardiac complications, with an estimated odds ratio (99% CI) of 0.98 (0.83, 1.16), P = .79. Conclusions: This is, by far, the largest clinical study for postoperative outcomes of SLE patients with adequately powered statistical analyses. We concluded that SLE was associated with a higher risk of renal complications and in-hospital mortality but not cardiac events after major surgery. In SLE patients, more aggressive measures should be taken to prevent renal injury in the perioperative period.