Minimal Clinically Important Difference and Patient Acceptable Symptom State After Total Abdominal Hysterectomy: Secondary Analysis of RCT Data.

Background Modern anesthesia focuses on the patient's perception of achieved pain relief rather than just statistical significance. The minimal clinically important difference (MCID) and the patient acceptable symptom state (PASS) are measures of patient-reported outcomes. MCID in pain scores refers to the minimum reduction in visual analogue scale (VAS) or numeric rating scale (NRS) scores that leads to a perceptible improvement in pain, although it may not necessarily indicate full pain relief. PASS, on the other hand, is the threshold beyond which patients consider themselves to be in an acceptable state of well-being. These patient-centered outcomes reflect the clinical significance of the achieved pain relief from the patient's perspective. Furthermore, these metrics can guide anesthesiologists toward postoperative pain management targets. The purpose of this study was to determine the MCID in NRS scores and PASS after total abdominal hysterectomy (TAH). Methods This study represents a secondary analysis of a double-blind, randomized controlled trial (RCT) evaluating quadratus lumborum block (QLB) in total abdominal hysterectomy. The primary outcome was to determine the distribution-based MCID in NRS scores. The MCID was calculated as the average of three values derived from distinct distribution-based methods: (1) a proportion of the pooled standard deviation (SD), (2) a proportion of the standard error of measurement (SEM) in the control group, and (3) 10% of the scale range. The secondary outcome was to assess PASS. PASS was determined using the "threshold approach," identifying the pain score threshold that most accurately predicted patient satisfaction with pain relief. This was achieved by determining the value that yielded the best sensitivity and specificity in a receiver operating characteristic (ROC) curve analysis. Results The MCID for pain intensity, calculated as the mean value (1.5) derived from three distribution-based methods, represents the threshold for meaningful improvement. Concurrently, an NRS score of ≤3.5 was identified as the PASS threshold, indicating a high probability of patient satisfaction. This value defines the treatment target representing an acceptable level of symptom control. Conclusion Our findings establish an MCID of 1.5 and a PASS of ≤3.5 for NRS pain scores following total abdominal hysterectomy, defining clinically meaningful improvement and treatment targets to support more personalized and effective postoperative pain management.