Psychometric properties of the Persian version of the Mishel's Uncertainty in Illness Scale in Patients with Cancer.

Abstract: Purpose: Uncertainty is a major component in the illness experiences which extraordinarily can affect the psychological adjustment and the illness outcomes. Uncertainty in illness is defined as inability to define the illness-related events to the illness or disability in predicting the illness outcomes. The present study aimed to translate the Persian version of Uncertainty in Illness Scale (MUIS-A) and to investigate its psychometric properties on patients with cancer. Method: In this methodological study, validation of the Persian version of MUIS-A was performed in Iran on 420 cancer patients attending two major hospitals in Tehran, Iran. The scale was translated into Persian and back translated into English and revised according to editorial comments of the scale designers. Then, content and face validity, construct validity, internal consistency reliability and stability of the Persian version were measured. Data were analyzed using SPSS version 16 and LISREL 8.5. Results: Mean of the participants MUIS-A score was 90.1 (16.8). Confirmatory factor analysis confirmed validity of the whole instrument and its four subscales. The consistency of the instrument with a three-week interval was r = 0.91. Cronbach's alpha was 0.89 for the whole scale of 32 MUIS-A items and α = 0.58–0.86 for its four factors. Conclusions: The Persian version of the MUIS-A has good psychometric properties. It can be used to assess uncertainty in illness in Iranian patients with cancer. [Copyright &y& Elsevier]