Validation of the Persian version of the Pittsburgh Sleep Quality Index in elderly population

OBJECTIVE: The purpose of this study is to determine the validity and reliability of the Persian version of the Pittsburgh Sleep Quality Index in the elderly population. MATERIAL AND METHODS: A methodological study was conducted as a confirmatory factor analysis. Totally, 598 elderly people were selected through cluster sampling. In addition to analyzing the three-factor structure of PSQI, internal consistency reliability, structural validity, and its concurrent validity were examined. The structural credibility of PSQI was examined using other similar tools such as Sleep Health, Epworth Sleepiness, Insomnia Severity, Global Sleep Assessment, and Berlin indices. Finally, the concurrent criterion validity of PSQI was evaluated through multivariable regression analysis and all statistical analyzes were performed using SPSS and AMOS software. RESULTS: The reliability of the test according to Cronbach's alpha was 0.81. Confirmatory factor analysis indicators supported goodness of fit of the structural equation model. The confirmatory factor analysis showed that the ratio of χ(2)/ DF was 2.66 for the three-factor structure of PSQI and the goodness of fit indices of model were acceptable for this structural model (RMSEA=0.053, CFI=0.98, TLI=0.96, NFI=0.97, GFI=0.99). In addition, the internal consistency of the PSQI was 0.81 and the scales correlation score ranged from 0.48 to 0.71. CONCLUSION: The results indicated that Persian version of Pittsburgh Sleep Quality Index had the required validity and reliability for the elderly population of Iran and it can be used as a useful tool by other studies.