Psychometric evaluation and measurement invariance of the Sexual and Relationship Distress Scale in cancer and nonclinical general reproductive-age populations.

Background: The Sexual and Relationship Distress Scale (SaRDS) is a validated instrument developed in English to assess intra-personal and inter-personal distress experienced by individuals and their partners in the context of sexual dysfunction. However, it has not yet been translated into Chinese nor psychometrically evaluated within Chinese clinical cancer and nonclinical populations. Objective: This study aimed to translate the SaRDS into Chinese and assess its psychometric properties and measurement invariance across different populations (colorectal cancer [CRC] patients vs. nonclinical general reproductive-age adults) and across gender groups (male vs. female). Methods: Three phases were undertaken: (a) transcultural adaptation, (b) pre-testing, and (c) psychometric evaluation. Transcultural adaptation included translations and expert panels, the pre-testing was conducted in 20 participants. The psychometric evaluation was tested among 486 CRC patients and 536 nonclinical general reproductive-age populations. Outcomes: The Chinese version of the SaRDS was consistent with the original version, including 30 items and 14 factors. Results: Confirmatory factor analysis supported the 14-factor structure of the original SaRDS construct. The composite reliability and the average variance extracted indicated the SaRDS had good convergent validity. Measurement invariance analyses indicated that the factor structure, factor loadings, and item intercepts of the SaRDS were invariant across CRC and nonclinical general populations, as well as across gender groups. The correlation of SaRDS with the Arizona Sexual Experience Scale and the Quality of Relationship Index showed good criterion-related validity. Moreover, the SaRDS and subscales had high internal consistency. Clinical implications: The Chinese version of the SaRDS is a psychometrically robust tool suitable for evaluating individual and relationship distress related to sexual dysfunction among clinical cancer and nonclinical general populations. The 14 domains provided by the SaRDS enable clinicians to identify specific areas of distress, facilitating accurate assessment and tailored interventions for individuals and couples experiencing sexual difficulties. Strengths and limitations: This study provides the first evidence of measurement invariance of the SaRDS across cancer patients, nonclinical general populations, and gender groups. However, due to its cross-sectional design, future longitudinal studies are needed to further examine the temporal stability and measurement invariance over time. Conclusion: Our findings suggest that the Chinese version of the SaRDS is a reliable, valid, and psychometrically sound instrument for assessing sexual and relationship distress in clinical cancer and nonclinical reproductive-age populations. Its demonstrated measurement invariance across populations and genders supports its broad applicability in clinical practice and research.