Estimating minimal, moderate, and marked clinically important differences for patient reported outcome measure in randomised controlled trial

作者：Jiani Wu, Liang Yao, Kuan Liao, Janelle Yorke, Yongpei Yu, Zhishun Liu, Xiaomei Yao, Zongshi Qin · 发表于：Chinese Medical Journal · 年份：2026 · DOI：10.1097/cm9.0000000000004084 · 被引用次数：6 · 研究领域：Urinary Bladder and Prostate Research、Acupuncture Treatment Research Studies、Sexual function and dysfunction studies

BACKGROUND: Patient-reported outcome measures (PROMs) are increasingly used in clinical trials, yet thresholds that define clinically important difference (CID) within patients and treatment effects beyond placebo remain inconsistently reported, limiting its utility in clinical research and practice. Using chronic pelvic pain and its core PROM as a worked example, the study aims to present a structured framework for CID thresholds that separates within-group change from between-group difference in treatment effect, each further stratified as minimal, moderate, and marked. METHODS: We used data from a multicenter randomized controlled trial of acupuncture vs . sham acupuncture in 440 men with chronic prostatitis (CP)/chronic pelvic pain syndrome (CPPS) conducted from October 2017 to April 2019. National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) served as the PROM and the Patient Global Impression of Change (PGI-C) as the anchor. CIDs were estimated using a linear mixed-effects model to assess changes in NIH-CPSI scores across PGI-C categories. RESULTS: At the end of treatment, 12.3% (51/414) participants reported no change, 34.1% (141/414) slight improvement, 32.1% (133/414) moderate improvement, and 19.6% (81/414) marked improvement; and 1.9% (8/414) reported worsening. The estimated Clinically important within-group difference (CIDs within-group ) in NIH-CPSI total score was 4.6 points for minimal, 6.0 points for moderate, and 7.3 points for marked im...