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

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