The association of payer type and opioid use on functional improvement at short-term follow-up after lumbosacral transforaminal epidural steroid injection: Results of a large registry study.

Background: Lumbosacral transforaminal epidural steroid injection (LTFESI) is a commonly performed intervention for treating radicular pain. While factors that predict pain improvement after LTFESI have been evaluated, minimal literature exists regarding predictors of functional improvement. Purpose: To identify factors that are associated with functional improvement at short-term follow-up after LTFESI. Study design: Retrospective review of prospectively collected registry data. Patient sample: Patients undergoing LTFESI at an academic spine center who completed an Oswestry Disability Index (ODI) questionnaire both pre-procedure and one to three weeks post-procedure. Outcome measures: The outcomes of interest were the proportions of patients who experienced a minimal clinically important difference (MCID) in function defined as ​≥ ​30% improvement in ODI score, as well as ​≥ ​10-point and ≥15-point improvement in ODI score. Methods: Logistic regression analysis was performed to examine the associations of predictor variables to the ODI responder/non-responder outcome variable. The predictor variables for the analysis included: age, baseline ODI score, Charleston Comorbidity Index (CCI), payer type, prior lumbosacral spine surgery, pre-injection opioid use, two-level injections, bilateral injections, repeat injection, trainee presence during injection, immediate numerical rating scale (NRS) change post-injection. An odds ratio (OR) and its 95% confidence intervals (CIs) were calculated. Results: A total of 606 patients were included in the analysis. More than half of the patients (56.8%) reported a ≥7.1% improvement in ODI score, and about 30% reported a ≥30% improvement in ODI score. Approximately 36% and 20% of the patients reported ≥10-point and ≥15-point reductions in ODI score, respectively. Medicaid and Medicare payer type and pre-injection opioid use were significantly associated with a lower likelihood of ≥30%, and ≥15-point improvements in ODI, after adjusting for the other factors ( Conclusions: When using various common definitions of MCID for ODI score improvement, Medicaid, Medicare, and pre-injection opioid use were identified as factors that are negatively associated with functional improvement at short-term follow-up after LTFESIs.