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

Abstract

BackgroundLumbosacral 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. PurposeTo identify factors that are associated with functional improvement at short-term follow-up after LTFESI. Study designRetrospective review of prospectively collected registry data. Patient samplePatients 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 measuresThe 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. MethodsLogistic 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. ResultsA 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 (p ​< ​0.05). ConclusionsWhen 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.