Preliminary identification of psychometric cut-off points for the SQoL-CHD: a cross-sectional study based on LPA and ROC analyses in a Chinese clinical sample

Objective: To determine psychometric cut-off points for the male and female versions of the Sexual Quality of Life Questionnaire for Coronary Heart Disease (SQoL-CHD), and to validate their effectiveness in distinguishing patients with low vs. high sexual quality of life, as well as their association with psychological distress. Methods: A cross-sectional study using convenience sampling was conducted among 1,368 patients with coronary heart disease from a large general hospital in Henan Province, China between March and December 2024. The sexual quality of life questionnaire for patients with coronary heart disease (male version and female version), the Generalized Anxiety Scale (GAD-7) and the Patient Health Questionnaire-9 (PHQ-9) were used for measurement. LPA was used to identify latent classes of sexual quality of life, and then ROC analysis was used to determine the optimal cut-off point, and its validity was verified by anxiety and depression levels. Results: LPA results show, the sexual quality of life for both male and female patients was classified into three latent classes, demonstrating high classification accuracy (Entropy > 0.96). ROC analysis determined that the optimal cut-off point for the female version of the questionnaire was 58 (sensitivity 96.8%, specificity 96.6%, AUC = 0.997), and that for the male version was 68 (sensitivity 98.5%, specificity 99.0%, AUC = 0.999). The cut-off point validation results showed that the patients in the low sexual quality of life group had significantly higher scores in sexual physiology, sexual psychology, sexual cognition dimensions, as well as anxiety and depression levels than those in the high sexual quality of life group, and male patients had a higher risk of anxiety and depression. Conclusion: The SQoL-CHD questionnaire cut-off points demonstrate strong psychometric properties and are effective for identifying CHD patients at risk of low sexual quality of life and higher levels of anxiety and depression symptoms, supporting their use in targeted clinical screening and intervention.