Validation of PROMIS in Diverse Populations/Clinical Study: Measuring Change in Fatigue

Evaluate how well three different patient-reported outcomes (PROs) measure individual change. 214 patients (from two sites) initiating first or new chemotherapy for any stage of breast or gastrointestinal cancer participated. The 13-item FACIT–Fatigue scale, a 7-item PROMIS® Fatigue Short-Form (PROMIS 7a), and the PROMIS® Fatigue computer adaptive test (CAT) were administered monthly online for six months. Reliability of measured change was defined, under a population mixed effects model, as the ratio of estimated systematic variance in rate-of-change to the estimated total variance of measured individual differences in rate-of-change. Precision of individual measured change, the standard error of measurement (SEM) of change, was given by the square root of the rate-of-change sampling variance. Linear and quadratic models were examined up to 3 and up to 6 months. A linear model for the reliability of measured change showed the following by 6 and by 3 months, respectively: PROMIS CAT (0.363 and 0.342); PROMIS SF (0.408 and 0.533); FACIT (0.459 and 0.473). Quadratic models offered no noteworthy improvement over linear models. Both reliability and precision results demonstrate the need to improve the measurement of intra-individual change. These results illustrate the challenge of reliably measuring individual change in fatigue with a level of confidence required for intervention. Optimizing clinically useful measurement of intra-individual differences over time continues to pose a challenge for PROs.

本研究旨在评估三种不同的患者报告结局（Patient-Reported Outcomes，PROs）对个体变化的测量效能。研究纳入来自两个研究中心的214名患者，这些患者为首次接受化疗或启动新化疗方案的各分期乳腺癌或胃肠道癌症受试者。研究采用线上方式，在6个月的随访周期内每月完成一次评估，评估内容涵盖三款量表：包含13个条目的FACIT疲劳量表（FACIT–Fatigue scale）、含7个条目的患者报告结局测量信息系统（Patient-Reported Outcomes Measurement Information System，PROMIS®）疲劳简表（PROMIS 7a），以及PROMIS®疲劳计算机自适应测验（Computer Adaptive Test，CAT）。
本研究在群体混合效应模型（population mixed effects model）框架下，将测量变化的信度定义为：变化速率的估计系统方差与个体变化速率的总估计方差的比值。而个体测量变化的精度，即变化的测量标准误（Standard Error of Measurement，SEM），由变化速率的抽样方差的平方根计算得到。
本研究分别以3个月和6个月为随访截止节点，对线性模型与二次模型进行了检验。针对测量变化信度的线性模型结果显示，在随访6个月和3个月时，各项量表的信度分别为：PROMIS CAT（0.363与0.342）、PROMIS简表（0.408与0.533）、FACIT疲劳量表（0.459与0.473）。二次模型相较于线性模型，未展现出显著的性能提升。
无论是信度还是精度结果均表明，当前的个体内部变化测量手段仍有待优化。本研究结果凸显了在干预研究所需的置信水平下，可靠测量疲劳相关个体变化所面临的挑战。优化具备临床应用价值的跨时间个体差异测量方法，仍是患者报告结局领域亟待攻克的难题。