Frailty and postoperative outcomes in patients undergoing surgery for degenerative spine disease

Abstract

Background context: Frailty is defined as a state of decreased reserve and susceptibility to stressors. The relationship between frailty and postoperative outcomes after degenerative spine surgery has not been studied.

Purpose: This study aimed to (1) determine prevalence of frailty in the degenerative spine population; (2) describe patient characteristics associated with frailty; and (3) determine the association between frailty and postoperative complications, mortality, length of stay, and discharge disposition.

Study design: This is a retrospective analysis on a prospectively collected cohort from the National Surgical Quality Improvement Program (NSQIP).

Patient sample: A total of 53,080 patients who underwent degenerative spine surgery between 2006 and 2012 were included in the study.

Outcome measures: A modified frailty index (mFI) with 11 variables derived from the NSQIP dataset was used to determine prevalence of frailty and its correlation with a composite outcome of perioperative complications as well as hospital length of stay, mortality, and discharge disposition.

Methods: After calculating the mFI for each patient, the prevalence and predictors of frailty were determined for our cohort. The association of frailty with postoperative outcomes was determined after adjusting for known and suspected confounders using multivariate logistic regression.

Results: Frailty was present in 2,041 patients within the total population (4%) and in 8% of patients older than 65 years. Frailty severity increased with increasing age, male sex, African American race, higher body mass index, recent weight loss, paraplegia or quadriplegia, American Society of Anesthesiologists (ASA) score, and preadmission residence in a care facility. Frailty severity was an independent predictor of major complication (OR 1.15 for every 0.10 increase in mFI, 95%CI 1.09-1.21, p<.0005) and specifically predicted reoperation for postsurgical infection (OR 1.3, 95%CI 1.16-1.46, p<.0005). Prolonged length of stay and discharge to a new facility were also independently predicted by frailty severity (p<.0005). Frailty severity predicted 30-day mortality on unadjusted (OR 2.05, 95%CI 1.70-2.48, p<.0005) and adjusted analyses (OR 1.48, 95%CI 1.18-1.86, p<.0005).

Conclusions: Frailty is an important predictor of postoperative outcomes following degenerative spine surgery. Preoperative recognition of frailty may be useful for perioperative optimization, risk stratification, and patient counseling.

Keywords: Degenerative spine disease; Frailty; Morbidity; Outcomes; Risk stratification; Spine surgery.