Background Monitoring disease progression in childhood interstitial lung diseases (chILD) is essential. No information for the minimal important difference (MID), which is defined as the smallest change in a parameter that is perceived as important prompting a clinician to change the treatment, is available. We calculated MIDs for vital signs (respiratory rate, peripheral oxygen saturation in room air, Fan severity score) and health-related quality of life (HrQoL) scores. Methods This study used data from the Kids Lung Register, which is a web-based management platform that collects data of rare paediatric lung disorders with a focus on chILD. Data of vital signs and HrQoL scores (Health Status Questionnaire, chILD-specific questionnaire and PedsQL V.4.0) were collected. MIDs were calculated according to distribution-based (one-third SD) and anchor-based methods (using forced expiratory volume in 1 s and forced vital capacity) as anchors. Results Baseline data of 774 children were used to calculate the following MIDs: respiratory rate 1.3 (z-score), O2 saturation in room air 3.0%, Fan severity score 0.2–0.4, Health Status Questionnaire 0.4–0.8, chILD-specific questionnaire 4.4%–8.2%, physical health summary score 7.8%–8.9%, psychosocial health summary score 3.4%–6.9% and total score 5.1%–7.4%. Results of the responsiveness analysis generally agreed with the MIDs calculated. Conclusions For the first time, we provide estimates of MIDs for vital signs and HrQoL scores in a large cohort of chILD using different methods. Data are available on reasonable request.

中文翻译：

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儿童间质性肺病的最小重要差异

背景 监测儿童间质性肺病 (child) 的疾病进展至关重要。没有关于最小重要差异 (MID) 的信息可用，MID 被定义为被认为是促使临床医生改变治疗的重要参数的最小变化。我们计算了生命体征（呼吸频率、室内空气外周血氧饱和度、Fan 严重程度评分）和健康相关生活质量 (HrQoL) 评分的 MID。方法 本研究使用来自 Kids Lung Register 的数据，Kids Lung Register 是一个基于网络的管理平台，收集以儿童为重点的罕见小儿肺部疾病的数据。收集了生命体征和 HrQoL 评分（健康状况问卷、儿童特定问卷和 PedsQL V.4.0）的数据。MID 是根据基于分布（三分之一 SD）和基于锚点的方法（使用 1 秒用力呼气量和用力肺活量）作为锚点计算的。结果 774 名儿童的基线数据用于计算以下 MID：呼吸频率 1.3（z 评分），室内空气中的 O2 饱和度 3.0%，风扇严重程度评分 0.2-0.4，健康状况问卷 0.4-0.8，儿童特定问卷 4.4 %–8.2%，身体健康总分 7.8%–8.9%，心理社会健康总分 3.4%–6.9%，总分 5.1%–7.4%。反应性分析的结果与计算的 MIDs 大体一致。结论 我们首次使用不同方法对大量儿童队列中的生命体征和 HrQoL 评分的 MID 进行了估计。可应合理要求提供数据。