Merck & Co., Inc., Kenilworth, NJ, USA.
Evidera Inc., Bethesda, MD, USA.
Ther Adv Respir Dis. 2021 Jan-Dec;15:17534666211049743. doi: 10.1177/17534666211049743.
Patients with chronic cough experience considerable burden. The cough severity visual analog scale (VAS) records patients' assessment of cough severity on a 100-mm linear scale ranging from "no cough" (0 mm) to "worst cough" (100 mm). Although cough severity scales are widely used in clinical practice and research, their use in patients with refractory or unexplained chronic cough has not been formally validated.
This analysis includes data from a phase 2b randomized controlled trial of the P2X3-receptor antagonist gefapixant for treatment of refractory or unexplained chronic cough (NCT02612610). Cough severity VAS scores were assessed at baseline and Weeks 4, 8, and 12. The cough severity VAS was validated using several outcomes, including the Cough Severity Diary (CSD), Leicester Cough Questionnaire (LCQ), patient global impression of change (PGIC) scale, and objective cough frequency. Validation metrics included test-retest reliability, convergent and known-groups validity, responsiveness, and score interpretation (i.e., clinically meaningful change threshold).
The analysis included 253 patients (median age, 61.0 years; females, 76%). Test-retest reliability of the cough severity VAS was moderate (intraclass correlation coefficient, 0.51). The cough severity VAS had acceptable convergent validity with other related measures (Pearson of 0.53 and -0.41 for CSD and LCQ total scores, respectively; < 0.0001 for each). Known-groups validity was supported by significant differences in mean cough severity VAS scores across severity groups defined using CSD, LCQ, and cough frequency tertiles. A large effect size was observed in patients with the greatest improvements in PGIC (Cohen = -1.8). A ⩾ 30-mm reduction in the cough severity VAS was estimated as a clinically meaningful change threshold for clinical trials in chronic cough.
The cough severity VAS is a valid and responsive measure. A cough severity VAS reduction of ⩾ 30 mm can discriminate clinically meaningful changes in chronic cough severity in clinical studies.
慢性咳嗽患者承受着相当大的负担。咳嗽严重程度视觉模拟量表（VAS）记录了患者在 100 毫米线性量表上对咳嗽严重程度的评估，范围从“无咳嗽”（0 毫米）到“最严重咳嗽”（100 毫米）。尽管咳嗽严重程度量表在临床实践和研究中得到广泛应用，但尚未对难治性或不明原因的慢性咳嗽患者进行正式验证。
本分析包括一项 P2X3 受体拮抗剂 gefapixant 治疗难治性或不明原因慢性咳嗽的 2b 期随机对照试验（NCT02612610）的数据。在基线和第 4、8 和 12 周评估咳嗽严重程度 VAS 评分。使用咳嗽严重程度日记（CSD）、莱斯特咳嗽问卷（LCQ）、患者总体印象变化量表（PGIC）和客观咳嗽频率等几种结果验证咳嗽严重程度 VAS。验证指标包括重测信度、收敛和已知组有效性、反应性以及评分解释（即临床有意义的变化阈值）。
分析纳入了 253 名患者（中位年龄 61.0 岁；女性 76%）。咳嗽严重程度 VAS 的重测信度为中度（组内相关系数为 0.51）。咳嗽严重程度 VAS 与其他相关测量方法具有良好的收敛有效性（CSD 和 LCQ 总分的 Pearson 分别为 0.53 和-0.41；每个均为 <0.0001）。使用 CSD、LCQ 和咳嗽频率三分位数定义的严重程度组之间咳嗽严重程度 VAS 评分的显著差异支持了已知组有效性。在 PGIC 改善最大的患者中观察到较大的效应量（Cohen 为-1.8）。咳嗽严重程度 VAS 减少 30mm 以上被估计为慢性咳嗽临床试验中临床有意义的变化阈值。
咳嗽严重程度 VAS 是一种有效且敏感的测量方法。咳嗽严重程度 VAS 减少 30mm 以上可以区分慢性咳嗽严重程度在临床研究中的临床有意义的变化。
