Clinical Depression Is a Strong Predictor of Poor Lumbar Fusion Outcomes Among Workers' Compensation Subjects

Study Design. Retrospective cohort study. Objective. Determine how psychosocial factors, particularly depression, impact lumbar fusion outcomes in a workers' compensation (WC) setting. Summary of Background Data. WC patients are less likely to return to work (RTW) after fusion. Few studies evaluate risk factors within this clinically distinct population. Methods. A total of 2799 Ohio WC subjects were identified who underwent lumbar fusion between 1993 and 2013 using Current Procedural Terminology (CPT) procedural and International Classification of Diseases, Ninth Revision (ICD-9) diagnosis codes. A total of 123 subjects were diagnosed with depression before fusion. Subjects with a smoking history, prior lumbar surgery, permanent disability, and failed back syndrome were excluded. The primary outcome was whether subjects returned to work within 2 years of fusion and sustained this RTW for more than 6 months of the following year. To determine the impact depression had on RTW status, we performed a multivariate logistic regression analysis. We also compared time absent from work and other secondary outcomes using chi(2) and t tests. Results. Subjects with preoperative depression had significantly higher rates of legal representation, degenerative lumbar disease, and higher medical costs, and used opioid analgesics for considerably longer before and after fusion (P < 0.001). Depression group (10.6% [13/123]) and controls (33.0% [884/2676]) met our RTW criteria (P < 0.001). Preoperative depression was a negative predictor of RTW status (P < 0.001; odds ratio [OR]: 0.38). Additional predictors included working during same week as fusion (OR: 2.15), age more than 50 years (OR: 0.58), chronic preoperative opioid analgesia (OR: 0.58), and legal representation (OR: 0.64). After surgery, depression subjects were absent from work 184 more days compared with controls (P < 0.001). Conclusion. Overall, RTW rates after fusion were low, which was especially true for those with pre-existing depression. Depression was a strong negative predictor of postoperative RTW status. Psychological screening and treatment may be beneficial in these subjects. The poor outcomes in this study may highlight a more limited role for fusion among WC subjects with chronic low back pain where RTW is the treatment goal.