The impact of frailty on patient-reported outcomes after elective thoracolumbar degenerative spine surgery

Abstract

OBJECTIVE Frailty has been shown to be a risk factor of perioperative adverse events (AEs) in patients undergoing various types of spine surgery. However, the relationship between frailty and patient-reported outcomes (PROs) remains unclear. The primary objective of this study was to determine the impact of frailty on PROs of patients who underwent surgery for thoracolumbar degenerative conditions. The secondary objective was to determine the associations among frailty, baseline PROs, and perioperative AEs. METHODS This was a retrospective study of a prospective cohort of patients older than 55 years who underwent surgery between 2012 and 2018. Data and PROs (collected with EQ-5D, Physical Component Summary [PCS] and Mental Component Summary [MCS] of SF-12, Oswestry Disability Index [ODI], and numeric rating scales [NRS] for back pain and leg pain) of patients treated at a single academic center were extracted from the Canadian Spine Outcomes and Research Network registry. Frailty was calculated using the modified frailty index (mFI), and patients were classified as frail, prefrail, and nonfrail. A generalized estimating equation (GEE) regression model was used to assess the association between baseline frailty status and PRO measures at 3 and 12 months. RESULTS In total, 293 patients with a mean ± SD age of 67 ± 7 years were included. Of these, 22% (n = 65) were frail, 59% (n = 172) were prefrail, and 19% (n = 56) were nonfrail. At baseline, the three frailty groups had similar PROs, except PCS (p = 0.003) and ODI (p = 0.02) were worse in the frail group. A greater proportion of frail patients experienced major AEs than nonfrail patients (p < 0.0001). However, despite the increased incidence of AEs, there was no association between frailty and postoperative PROs (scores on EQ-5D, PCS and MCS, ODI, and back-pain and leg-pain NRS) at 3 and 12 months (p ≥ 0.05). In general, PROs improved at 3 and 12 months (with most patients reaching the minimum clinically important difference for all PROs). CONCLUSIONS Although frailty predicted postoperative AEs, mFI did not predict PROs of patients older than 55 years with degenerative thoracolumbar spine after spine surgery.