Abstract
BACKGROUND: Poor sleep quality predicts poor quality of life, poor self-rated health, and chronic diseases and mental disorders among older adults. The Pittsburgh Sleep Quality Index (PSQI) is the most widely used self-report measure of sleep quality in older adults. OBJECTIVES: This study aimed to assess internal reliability, face validity, content validity and internal consistency of the Slovenian version of the PSQI (PSQI-SLO) for sleep quality in older adults. METHODS: A cross-sectional study was used to evaluate content and face validity as well as reliability (ɑ, ω and item-total correlations). Residents of 13 nursing homes and community-dwelling older adults from all regions of Slovenia were sampled. A total of 831 participants aged 65 years and older participated in the study between March and August 2019. RESULTS: All items were successfully translated to Slovenian. A minor cultural adaptation was made to improve the clarity of the meaning of all items. None of the items had an item content validity index (I-CVI) score lower than 0.50. Kappa indices were excellent for half of the items and good for the remainder. Internal consistency agreed with prior research (ɑ = 0.74). Intraclass correlation coefficient for global PSQI-SLO was 0.62 (p < 0.001). The total score of PSQI-SLO (8.09 ± 3.64 (95%, CI = 7.85-8.34)) was expected and comparable. Fifty-eight and four tenths' per cent (95%, CI = 55%-62%) had at least one chronic disease and 40% (95%, CI = 37%-42%) lived in a nursing home. CONCLUSIONS: PSQI-SLO showed adequate internal consistency and test-retest reliability, and adequate construct and criterion validity. The instrument can be important in assessing older adults' subjective sleep quality in nursing homes, home environment and clinical settings.