Responsiveness and Minimal Clinically Important Difference of the Turkish Version of the Oswestry Disability Index in Patients With Acute Discogenic Lumbar Radiculopathy

This study aimed to determine the responsiveness and establish the minimal clinically important difference of the Turkish version of the Oswestry Disability Index (ODI-TR) in patients with acute discogenic lumbar radiculopathy (ADLR). This study included 140 patients (mean age: 51.38 ± 12.23 years) with ADLR. Pre- and post-treatment, participants completed the ODI-TR and the Visual Analogue Scale (VAS), which assessed pain at rest (VASr), at night (VASn), and during activity (VASa). Post-treatment, the Global Perceived Effect Scale (GPE) was utilized to quantify patient-reported improvement or deterioration. Responsiveness was evaluated using both distribution- and anchor-based methods. The distribution-based approach involved calculating the standard error of measurement (SEM) using the formula SEM = SDx√(1-R), followed by the determination of the minimum detectable change at a 95% confidence level (MDC95), calculated as MDC = SEMx1.96x√2. The anchor-based method employed receiver-operating characteristic (ROC) curve analysis. The ODI-TR demonstrated good responsiveness, as indicated by an effect size of 1.29 and a standardized response mean of 1.03. The measurement error was quantified by an SEM of 7.08, and the MDC was calculated as 19.62. The ROC analysis showed a moderate ability to distinguish between patient outcomes, with an area under the curve of 0.71. An ODI-TR score of 9.50 was found to be the most effective cut-off, providing high sensitivity (86.1%) and specificity (76.0%). The ODI-TR is responsive in determining the changes in ADLR patients. The MDC and established cut-off point provide clinicians with valuable metrics for discerning clinically significant improvements or deteriorations.