Correlation of responsiveness to pain intensity and functional status measurements after lumbar epidural steroid injection in patients with lower back pain

Abstract

This study aimed to examine the changes in the Numerical Rating Scale (NRS), Oswestry Disability Index (ODI), and Roland Morris Disability Questionnaire (RMDQ) scores before and after epidural steroid injection (ESI) in patients with lower back pain, and the correlation between the three scales in patients with reduced scores on these scales. Patients completed the NRS, ODI, and RMDQ before and after receiving ESI. A paired t-test was performed to compare the mean scores obtained before and after ESI. The correlations between the scores were estimated by calculating the difference between the baseline and follow-up scores. Of the 49 patients, 37 completed both questionnaire assessments. Among them, 26 patients (70%) presented a post-ESI decrease in scores obtained on all three scales. The NRS score decreased from 6.81±1.91 points at baseline to 3.66±2.22 points at follow-up (p<0.0001); similarly, the ODI score decreased from 41.65±14.76 to 30.38±16.16 points (p=0.0025); and the RMDQ score decreased from 11.11±5.68 to 7.64±5.74 points (p=0.011). Of the 37 patients who completed the two questionnaires, 26 had reduced NRS, ODI, and RMDQ scores. The intraclass correlation coefficients between the NRS and ODI, NRS and RMDQ, and ODI and RMDQ scores were 0.7943, 0.6615, and 0.7182, respectively. The concordance correlation coefficients between the NRS and ODI, NRS and RMDQ, and ODI and RMDQ scores were 0.6020, 0.4938, and 0.5202, respectively. Among the measurements, the correlation between the NRS and ODI scores was the highest, and a moderate correlation was found between the scores obtained using the other instruments.