The Quebec Task Force classification (QTF) was originally designed to help in making a clinical decision and to aid in determining the prognosis. However, the predictive validity and prognostic significance of the classification was debated. We conducted the study to determine the discriminative and prognostic significance of the modified Quebec Task Force classification in chronic low back pain patients
Materials & Methods: 183 consecutive chronic low back pain(>7 weeks of continuous pain) patients in the age groups of 18-65 years who presented to a tertiary care centre in South India and followed up for a minimum of 6 months were included in the study. Patients were assigned to one of the four QTF categories after a detailed history and examination. Pain severity and functional disability were assessed using LBPRS and RMDQ respectively. The patients were then put on the common specific rehabilitation protocol and analgesics, and followed up every six weeks to look for compliance with the treatment. The scores (LBPRS, RMDQ) were noted again at 3 and 6 months. The comparison of scores was done among the 4 QTF categories at the time of presentation, at 3 months and at 6 months
Result: There were no significant differences in the distribution of age, sex, occupation or educational status among different QTF categories. Non-parametric tests using Wilcoxon Signed Rank test showed significant improvement in LBPRS and RMDQ scores with time in each category(p value <0.001).On LBPRS scale, QTF 1 improved the most from baseline after 6 months (42.3%). QTF 4 improved more (24.6%) compared to QTF 2(21.58%) and QTF 3(19.87%).On RMDQ scale, Category 1 and 4 improved more (20.35% and 20.82% respectively) compared to category 2 and 3(11.81% and 9.1% respectively).
Conclusion: All the four QTF categories showed a significant improvement of pain and activity limitation from the baseline at the end of 6 months with the physiotherapy rehabilitation. However, patients with nerve root signs treated non-surgically had a better outcome compared to those with radiating pain with no nerve root involvement. Patients with radiation below the knee and negative nerve root signs had the worst outcome in terms of pain and activity limitation at the end of six months. It validates the QTF classification as a prognostic label in patients treated with physiotherapy.