Minimal Clinically Important Difference in Patients with Acute Neck Pain Undergoing Conservative Treatment with Korean Medicine.

Purpose: To determine the minimal clinically important difference (MCID) and substantial clinical benefit (SCB) for patients with acute neck pain undergoing conservative treatment. Patients and Methods: This secondary data analysis of a randomized controlled trial investigated 128 individuals with acute neck pain receiving conservative treatment. The MCID and SCB of pain, functional disability, and quality of life were assessed using anchor-based methods. Patients' global impression of changes at week 9 was used as the anchor. A receiver operating characteristic curve was constructed, and the Youden index was employed to determine the optimal cut-off point. Area under the curve (AUC) values were calculated to assess accuracy. Minimal detectable changes (MDCs) were estimated using a distribution-based approach. Results: The study cohort comprised 60.2% female patients with an average age of 40.7 ± 12.7 years. The visual analog scale (VAS) score for pain during movement at baseline was 64.5 ± 10.6. The outcome measures' estimated MCID values (AUC) were as follows: VAS for pain during movement, -19.9 (0.89) and at rest, -17.5 (0.83); Northwick Park Neck Pain Questionnaire score, -14.7 (0.78); neck disability index, -10.6 (0.77); and physical component summary (PCS), 2.0 (0.83). The SCB estimates indicated thresholds of outcome improvement to be 1.5-3-fold higher. The MDC for PCS (9.49) exceeded its MCID and SCB. Conclusion: This study provides estimates for multidimensional MCID and SCB in acute neck pain treated conservatively. These values may assist clinicians in interpreting outcomes and setting meaningful treatment goals in clinical practice.