Validation of the simplified cough symptom score in non-small cell lung cancer patients after surgery

Background: The simplified Cough Symptom Score (sCSS) is a practical and simple tool for measuring cough severity. However, the sCSS is a consensus of experts, and has not been strictly validated among the non-small cell lung cancer (NSCLC) patients. We used the sCSS and investigated the validity, reliability, and repeatability of this instrument.

Methods: A total of 219 NSCLC patients completed the sCSS, Leicester Cough Questionnaire in Mandarin-Chinese (LCQ-MC) and cough Visual Analog Scale (VAS). 60 patients completed the LCQ and Global Rating of Change (GRC) at follow-up visits after 2-4 weeks. Concurrent validity, internal consistency, and repeatability were assessed.

Results: Analyses of concurrent validity showed significant correlations between the sCSS and the LCQ-MC (r = - 0.356 to - 0.580) and cough VAS (r = 0.555). The correlation of the nighttime score with the LCQ-MC and cough VAS was more closely than that of the daytime score (r = - 0.364 to - 0.545 and r = 0.502 vs. r = - 0.233 to - 0.449 and r = 0.450). Internal consistency was acceptable (Cronbach's α of 0.74-0.90). The internal consistency of the sCSS between the nighttime and daytime scores was 0.428. The repeatability was high (intraclass correlation coefficients of 0.760).

Conclusion: The sCSS is a reliable, valid instrument for assessing postoperative cough in NSCLC patients.