Respiratory measurements, respiratory symptoms, and quality of life in ALS: results from the REVEALS study

<i>Objective</i>: Progressing respiratory weakness throughout the course of amyotrophic lateral sclerosis (ALS) is clinically associated with distressing symptoms, including dyspnea, orthopnea, and difficulty clearing secretions. Fatigue, poor sleep, and reduced quality of life are also considered to be associated with declining respiratory function. Respiratory measurements guide prescription of interventions, which aim to alleviate symptoms. The relationships between respiratory measurements and patient reported symptoms are currently unclear. <i>Method</i>: The REVEALS study was a longitudinal, observational, multisite study of decline in respiratory function in people with ALS attending six European centers. Respiratory measures (forced and slow vital capacity (F/SVC), sniff nasal inspiratory pressure (SNIP), and peak cough flow) were collected, as were the presence of respiratory symptoms and simple quality of life, fatigue and sleep measures. We used Bayesian’s multivariate models to explore the associations of the respiratory measures with outcome variables. <i>Results</i>: Two hundred and eighty participants completed in-person assessments over a median of 8 (IQR 2.3, 14.1) months, with 974 data collection timepoints. The probability of reporting symptoms including dyspnea, orthopnea, and difficulty clearing secretions increased with decreasing respiratory measurement scores. The probability of reporting moderately low quality of life and moderate fatigue also increased with decreasing test scores, but reported sleep quality was not associated with respiratory scores. <i>Conclusion</i>: Respiratory weakness in people with ALS was associated with symptoms including dyspnea, orthopnea, and difficulty clearing secretions. The probability of reporting symptoms increased incrementally as respiratory weakness increased, supporting the use of both respiratory measurements and the presence of symptoms in making decisions about clinical interventions.

<i>研究目标</i>: 肌萎缩侧索硬化症（amyotrophic lateral sclerosis, ALS）患者病程中逐渐进展的呼吸肌无力，临床常伴随呼吸困难、端坐呼吸及分泌物清除困难等困扰性症状。疲劳、睡眠质量不佳与生活质量下降也被认为与呼吸功能衰退相关。呼吸功能检测指标可指导旨在缓解症状的临床干预方案的制定，但目前呼吸检测指标与患者自述症状间的关联尚不明确。
<i>研究方法</i>: REVEALS研究是一项纵向观察性多中心研究，纳入就诊于欧洲6家医疗中心的ALS患者，旨在探究其呼吸功能的衰退情况。研究收集了多项呼吸功能检测指标，包括用力肺活量与慢肺活量（forced and slow vital capacity, F/SVC）、鼻吸气峰压（sniff nasal inspiratory pressure, SNIP）以及最高咳嗽峰流速，同时收集了呼吸症状相关信息，以及简化版生活质量、疲劳与睡眠质量评估数据。本研究采用贝叶斯多变量模型，探究呼吸检测指标与各结局变量间的关联。
<i>研究结果</i>: 共计280名参与者完成了面对面评估，中位随访时长为8个月（四分位数间距2.3~14.1个月），累计获取974个数据采集时间点的样本。患者报告呼吸困难、端坐呼吸及分泌物清除困难等症状的概率，随呼吸检测指标得分降低而逐渐升高；报告中重度生活质量下降与中度疲劳的概率，同样随检测得分降低而升高，但自述睡眠质量与呼吸检测指标得分无显著关联。
<i>研究结论</i>: ALS患者的呼吸肌无力与呼吸困难、端坐呼吸及分泌物清除困难等症状显著相关。随着呼吸肌无力程度加重，患者报告相关症状的概率逐步升高，这一结果支持在制定临床干预决策时，同时参考呼吸功能检测指标与患者自述的症状表现。