Construction and Preliminary Validation of the Chinese Assessment Scale for Zoster-associated Pain Based on the Delphi Method

This study aimed to develop and preliminarily validate a Chinese assessment scale for zoster-associated pain (ZAP) based on the Delphi method. A descriptive study was conducted. An initial item pool was developed based on domestic and international guidelines, expert consensus, and professional discussions related to ZAP. The Delphi method was employed in September 2023 to screen and revise the items, forming a preliminary version of the scale. From October 5, 2023, to January 31, 2024, a total of 209 patients with ZAP treated at the Department of Pain Management, The First Affiliated Hospital of Zhejiang University School of Medicine, were surveyed using this scale. Items were excluded using several criteria: standard deviation < 0.7 or coefficient of variation < 0.15 (dispersion trend method), correlation coefficient < 0.2 or non-significant differences (P > 0.05) (correlation analysis), non-significant differences (P > 0.05) (critical ratio method), and factor loadings < 0.4 or cross-loadings > 0.4 on multiple factors (exploratory factor analysis). Reliability was evaluated using internal consistency (Cronbach’s α), and validity was assessed through content and construct validity. Two rounds of Delphi expert consultation were conducted, involving 15 clinical pain specialists. A preliminary 16-item scale was developed based on threshold screening criteria. The response rate for both Delphi rounds was 100%, and the authority coefficients of experts were all > 0.7. Cronbach's α coefficients were 0.847 and 0.909 for the first and second rounds, respectively. Kendall’s W coefficients were 0.259 (χ² = 108.814, P < 0.001) and 0.291 (χ² = 74.130, P < 0.001) across the two rounds. Following item analysis of the 209 patient responses, 15 items were retained. The content validity of the scale was judged to be satisfactory by pain specialists. After further validity testing, 11 items were finally retained. The Kaiser-Meyer-Olkin (KMO) value was 0.837, and Bartlett’s test of sphericity was significant (P < 0.001). Exploratory factor analysis extracted three common factors, accounting for a cumulative variance contribution of 64.791%. The final Cronbach’s α coefficient was 0.808. The developed Chinese version of the ZAP assessment scale consists of 11 items across three dimensions, demonstrating good reliability, validity, and applicability.