Reliability and validity of the Persian version of patient assessment of constipation- quality of life (PAC-QOL) questionnaire

Aim The present study aimed to assess the reliability and validity of Persian version of patient assessment of constipation: quality of life (PAC-QOL) questionnaire in Iranian patients. Background Chronic constipation has significant effects on daily living, wellbeing and individuals' quality of life (QOL). Validated tools can help us to assessing QOL in affected ones and facilitating clinical management of them. Methods The English version of Patient Assessment of Constipation: Quality of Life (PAC-QOL) was translated into the Persian language and was confirmed by back-translation. One hundred and forty patients with functional constipation, according Rome III criteria, completed the questionnaires .The questionnaires were analyzed using Cronbach's Alpha internal consistency score to determine the reliability. Twenty medical experts were then asked to evaluate the PAC-QOL and the results were used to calculate the Content Validity Ratio (CVR) and Content Validity Index (CVI). Results Due to obtained value for Cronbach`s α (0.975) and also for the subscale of physical discomfort (0.930), psychosocial discomfort (0.975) and worries and concerns (0.915), the internal consistency is established. According to medical experts' opinions, the value of CVR ranged from 0.5 to 0.8 and the value of CVI was 0.81. Conclusion The Persian version of PAC-QOL questionnaire is shown to have acceptable reliability and validity to be used for psychometric evaluation in Iranian patients complaining of functional constipation.