Psychometric Validation and Setting Cutoff Point for Persian Version of World Health Organization Quality of Life-Old Questionnaire

Abstract

Health professionals assume the quality of life (QOL) as a main outcome of health care activities, especially in the elderly. Thus, they need valid tools for evaluating the effectiveness of their interventions. This study aimed to investigate the psychometric properties of the Persian version of the World Health Organization quality of life-old questionnaire (WHOQOL-OLD). The questionnaire was translated into Persian by standard translate/back-translate procedure. The Cronbach’s alpha and intra-class correlation (ICC) coefficients were estimated to assess the internal validity and reliability. Confirmatory factor analyses (CFA) in a sample of 300 Persian-speaking elderly in Shiraz, Iran, were used for construct validity assessment. ROC curve analysis was used to determine the cutoff point for poor or good QOL. All the analyses were conducted using SPSS 24 and IBM AMOS 24. The internal consistency and reliability indices of the Persian version of WHOQOL-OLD were acceptable (Cronbach’s alpha: 0.66–0.95; ICC: 0.71–0.91). CFA confirmed the WHOQOL-OLD six-domain structure (CMIN/ df = 3.12, p < .001; CFI = 0.93; NFI = 0.89; RMSEA = 0.08). The ROC curve indicated 71.5 as the best cutoff point, with a sensitivity of 82.3% and specificity of 61.8%. The Persian version of the WHOQOL-OLD is valid and can be used for investigating the QOL in Persian-speaking elderly.