INTRODUCTION: Psychological and behavioral factors are considered major risk factors of poor outcome after lumbar spine surgery. However, there is a need to explore the interactive effects of preoperative factors such as sleep disturbance and depression. The objective of this study was to examine the individual and combined association between preoperative sleep disturbance and depression on patient-reported disability and pain at one year after lumbar spine surgery. Understanding the influence of sleep disturbance and depression can inform evidence-based preoperative assessment and shared-decision making of preoperative and postoperative treatment.
METHODS: We analyzed prospectively collected multi-center registry data from 700 patients undergoing lumbar spine surgery (mean age = 60.9 years, 37% female, 89% white). Preoperative sleep disturbance and depression were assessed with PROMIS subscales. Established thresholds defined patients with moderate/severe sleep disturbance and depression. Outcomes for disability (Oswestry Disability Index) and back and leg pain (Numeric Rating Scales) were assessed preoperatively and at 12 months. We conducted separate regressions to examine the influence of preoperative sleep disturbance and depression on 12-month outcomes. Regressions examined each factor with and without accounting for the other, and in combination as a 4-level variable: 1) moderate/severe sleep disturbance alone, 2) moderate/severe depression alone, 3) both moderate/severe sleep disturbance and depression, 4) no moderate/severe sleep disturbance or depression. Covariates in regression models included age, sex, race, education, insurance, body mass index, smoking status, preoperative opioid use, fusion status, revision status, and preoperative outcome score.
RESULTS: When examined in isolation, 173 (35%) patients reported preoperative moderate/severe sleep disturbance and 130 (19%) patients reported moderate/severe depression. When examined in combination, 113 (17%) patients reported moderate/severe sleep disturbance alone, 70 (10%) reported moderate/severe depression alone, and 57 (8%) reported both moderate/severe sleep disturbance and depression. In independent models, preoperative sleep disturbance and depression were significantly associated with 12-month outcomes (p < 0.05). After accounting for depression, preoperative sleep disturbance was only associated with disability, while preoperative depression adjusting for sleep disturbance remained associated with all outcomes (p < 0.05). Patients reporting both moderate/severe sleep disturbance and moderate/severe depression had 12.6 points higher disability (95%CI = 7.4 to 17.8) and 1.5 points higher back (95% CI = 0.8 to 2.3) and leg pain (95% CI = 0.7 to 2.3) compared to patients without moderate/severe sleep disturbance or depression.
DISCUSSION: Preoperative sleep disturbance and depression are independent predictors of 12-month disability and pain when considered in isolation. The combination of sleep disturbance and depression impacts postoperative outcomes considerably. The high-risk group of patients with moderate/severe sleep disturbance and depression could benefit from targeted treatment strategies.