Psychometric properties of Pittsburgh Sleep Disturbance Index in Chinese breast cancer patients

Abstract

Background: The Pittsburgh Sleep Disturbance Index (PSQI) is an instrument used to measure the quality and patterns of sleep. This study aimed to evaluate the psychometric properties of the PSQI in Chinese breast cancer patients. Methods: Participants were 197 Chinese breast cancer patients (mean age = 49.4 years, SD = 7.9). They filled in the PSQI and self-reported measures on perceived stress, anxiety, depression, fatigue, pain, and quality of life. The PSQI assesses seven components of sleep: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction over the last month. Each component is scored on a 0 to 3 Likert scale, with higher scores denoting poorer sleep. The one-factor structure of the PSQI was evaluated via robust maximum likelihood confirmatory factor analysis using Mplus 7.11. Reliability and construct validity of the scale were assessed. Results: The revised one-factor model provided a good fit to the data (χ2(13) = 21.44, p > .05, CFI = .978, TLI = .965, RMSEA = .057, SRMR = .042). Factor loadings were statistically significant and ranged from .36 to .84. The global PSQI factor score had a satisfactory reliability coefficient (α = .79) and was significantly and negatively correlated with perceived stress, anxiety, depression, fatigue, pain severity, and pain interference (r = .29 - .51, p < .01) and negatively correlated with quality of life (r = -.56, p < .01). Conclusion: The results demonstrated satisfactory psychometric properties for the one-factor structure of the Chinese PSQI in terms of factorial validity, reliability, and construct validity in the breast cancer patients. Acknowledgement: This study was supported by the Research Grants Council General Research Fund (HKU745110H).