Psychometric properties of the Chinese version of the Pittsburgh Sleep Quality Index (PSQI) among Hong Kong Chinese childhood cancer survivors

Abstract

Background: Sleep disruption is a prevalent symptom reported by survivors of childhood cancer. However, there is no validated instrument for assessing this symptom in this population group. To bridge the literature gap, this study translated and adapted the Pittsburgh Sleep Quality Index (PSQI) for Hong Kong Chinese cancer survivors and examined its psychometric properties and factor structure. Methods: A convenience sample of 402 Hong Kong Chinese childhood cancer survivors aged 6–18 years were asked to complete the Chinese version of the PSQI, Center for Epidemiologic Studies Depression Scale for Children (CES-DC), Fatigue Scale-Child (FS-C)/Fatigue Scale-Adolescent (FS-A), and Pediatric Quality of Life Inventory (PedsQL). To assess known-group validity, 50 pediatric cancer patients and 50 healthy counterparts were recruited. A sample of 40 children were invited to respond by phone to the PSQI 2 weeks later to assess test–retest reliability. A cutoff score for the translated PSQI used with the survivors was determined using receiver operating characteristic analysis. Results: The Chinese version of the PSQI had a Cronbach alpha of 0.71, with an intraclass correlation coefficient of 0.90. Childhood cancer survivors showed significantly lower mean PSQI scores than children with cancer, and significantly higher mean scores than healthy counterparts. This reflected that childhood cancer survivors had a better sleep quality than children with cancer, but a poorer sleep quality than healthy counterparts. We observed positive correlations between PSQI and CES-DC scores and between PSQI and FS-A/FS-C scores, but a negative correlation between PSQI and PedsQL scores. The results supported that the Chinese version of the PSQI showed convergent validity. Confirmatory factor analysis showed that the translated PSQI data best fit a three-factor model. The best cutoff score to detect insomnia was 5, with a sensitivity of 0.81 and specificity of 0.70. Conclusion: The Chinese version of the PSQI is a reliable and valid instrument to assess subjective sleep quality among Hong Kong Chinese childhood cancer survivors. The validated PSQI could be used in clinical settings to provide early assessments for sleep disruption. Appropriate interventions can therefore be provided to minimize its associated long-term healthcare cost.