P.087 Association of pre-operative hyponatremia with morbidity and mortality in patients undergoing elective degenerative spine surgery

Background: Hyponatremia has been found to be associated with increased complications in a variety of surgical populations. No study looked specifically at patients undergoing spine surgery. We also specifically address whether it has an effect on the typical low-risk patient admitted for degenerative spine disease, a population that forms the major bulk of clinical practice. Methods: Data was obtained from the American college of surgeons National Surgical Quality Improvement Program (ACS-NSQIP). All patients who underwent elective spinal surgery for degenerative disease from 2011 to 2013 were included. The two arms (normonatremic and hyponatremic) were then compared. Results: A total of 58049 patients were included, 3037 were hyponatremic. Hyponatremic patients were older and had more comorbidities. They also developed more minor and major complications. When all comorbidities were controlled for, hyponatremia was only associated with increased minor but not major complications. These patients were more likely to require a blood transfusion (OR=1.23, CI 1.10-1.43) and a prolonged hospital stay (OR=1.52, CI 1.33-1.75). Conclusions: This study finds an association between hyponatremia and postoperative adverse events in a low risk population that forms the major bulk of clinical practice. This addresses a potential target for quality improvement strategies with significant cost saving implications.