Department of Dermatology, St George Hospital, Sydney, NSW, Australia.
Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
Br J Dermatol. 2024 Oct 17;191(5):823-831. doi: 10.1093/bjd/ljae283.
Pemphigus is a rare autoimmune blistering disease with potentially life-threatening consequences. Establishing minimal clinically important differences (MCIDs) for disease severity scores like the Pemphigus Disease Area Index (PDAI) is crucial for assessing treatment efficacy.
To calculate MCIDs for both improvement and deterioration in PDAI scores in patients with pemphigus vulgaris (PV) and pemphigus foliaceus (PF), using the anchor-based method.
A total of 41 patients with pemphigus were recruited, with 35 meeting the MCID analysis criteria. The anchor-based method was used to calculate MCIDs for PDAI scores against the 15-point Likert scale and the Physician Global Assessment visual analogue scale (PGA-VAS) anchors. Receiver operating characteristic curves were employed to determine optimal MCID cutpoints with the highest Youden Index (J). The 15-point Likert scale scores the change in disease severity spanning from -7 to +7, designed to quantify the extent of disease improvement/deterioration since the preceding visit.
The MCID for improvement in PDAI activity scores was 2.65 points using the 15-point Likert scale (78.7% correct classification; sensitivity 75.9%; specificity 73.5%) and 2.5 points using the PGA-VAS as the anchor (78.0% correct classification; sensitivity 84.4%; specificity 68.2%). Given the slightly higher correct classification rate using the 15-point Likert scale anchor, the MCID of 2.65 points was selected for PDAI activity score improvement. In contrast, the MCID for deterioration consistently remained at 2.5 points for the 15-point Likert scale anchor (81.0% correct classification; sensitivity 72.7%; specificity 81.0%) and 2.5 points for the PGA-VAS anchor (70.9% correct classification; sensitivity 69.6%; specificity 76.9%).
This study marks the inaugural attempt at MCID determination for PDAI scores in pemphigus, filling a critical knowledge gap. The study's calculated MCIDs provide essential benchmarks for clinical trials, treatment evaluation and research design optimization. Future studies should explore international collaborations, to examine potential cross-cultural variations in MCIDs.
天疱疮是一种罕见的自身免疫性水疱病，可能导致危及生命的后果。确定天疱疮疾病面积指数（PDAI）等疾病严重程度评分的最小临床重要差异（MCIDs）对于评估治疗效果至关重要。
使用基于锚定的方法计算天疱疮寻常型（PV）和天疱疮落叶型（PF）患者 PDAI 评分改善和恶化的 MCIDs。
共招募了 41 名天疱疮患者，其中 35 名符合 MCID 分析标准。使用基于锚定的方法，根据 15 分李克特量表和医生整体评估视觉模拟量表（PGA-VAS）锚定来计算 PDAI 评分的 MCIDs。使用接收者操作特征曲线确定具有最高 Youden 指数（J）的最佳 MCID 切点。15 分李克特量表评分疾病严重程度的变化范围为-7 至+7，旨在量化自上次就诊以来疾病改善/恶化的程度。
使用 15 分李克特量表，PDAI 活动评分改善的 MCID 为 2.65 分（78.7%正确分类；敏感性 75.9%；特异性 73.5%），PGA-VAS 作为锚定时为 2.5 分（78.0%正确分类；敏感性 84.4%；特异性 68.2%）。由于使用 15 分李克特量表锚定时的正确分类率略高，因此选择 2.65 分作为 PDAI 活动评分改善的 MCID。相比之下，15 分李克特量表锚定的恶化 MCID 始终保持在 2.5 分（78.0%正确分类；敏感性 72.7%；特异性 81.0%）和 PGA-VAS 锚定的 2.5 分（70.9%正确分类；敏感性 69.6%；特异性 76.9%）。
本研究首次尝试确定天疱疮 PDAI 评分的 MCIDs，填补了关键的知识空白。研究中计算的 MCIDs 为临床试验、治疗评估和研究设计优化提供了重要的基准。未来的研究应探索国际合作，以研究 MCIDs 在跨文化方面的潜在差异。
