Study design: Retrospective cohort study.
Objective: To evaluate prescription opioid use after lumbar fusion for degenerative disc disease in a workers' compensation (WC) setting.
Summary of background data: Use of opioids for treating chronic low back pain has increased greatly. Few studies have evaluated risk factors for chronic opioid therapy (COT) among the clinically-distinct WC population.
Methods: We used "Current Procedural Terminology" and "International Classification of Diseases, Ninth Revision" codes to identify 1002 Ohio WC subjects who underwent lumbar fusion for degenerative disc disease from 1993 to 2013. Postoperative COT was defined as being supplied with opioid analgesics for greater than 1 year after the 6-week acute period after fusion. 575 subjects fit these criteria, forming the COT group. The remaining 427 subjects formed a temporary opioid group. To identify prognostic factors associated with COT after fusion, we used a multivariate logistic regression analysis.
Results: Returning to work was negatively associated with COT (P < 0.001; odds ratio [OR] 0.38). COT before fusion (P < 0.001; OR 6.15), failed back syndrome (P < 0.001; OR 3.40), additional surgery (P < 0.001; OR 2.84), clinically diagnosed depression (P < 0.001; OR 2.34), and extended work loss before fusion (P = 0.038; OR 1.61) were positively associated with COT. The rates of postoperative COT associated with these factors were 27.8%, 79.6%, 85.0%, 76.4%, 77.1%, and 61.3%, respectively. Higher preoperative opioid load (P < 0.001) and duration of use (P < 0.001) were positively associated with higher postoperative rates of COT. Within 3 years after fusion, the COT group was supplied with an average of 1083.4 days of opioids and 49.0 opioid prescriptions, 86.2% of which were Schedule II. The COT group had an 11.0% return to work rate, $27,952 higher medical costs per subject, 43.5% rate of psychiatric comorbidity, 16.7% rate of failed back syndrome, and 27.7% rate of additional lumbar surgery.
Conclusion: The majority of the study population was on COT after fusion. COT was associated with considerably worse outcomes. The poor outcomes of this study could suggest a more limited role for discogenic fusion among WC patients.
Level of evidence: 3.