Validation of an uncertainty of illness scale adapted to use with Spanish emergency department patients and their accompanying relatives or friends.

Objectives: To validate a Spanish adaptation of the Mishel Uncertainty of Illness Scale for use with emergency-department (ED) patients and their accompanying relatives or friends (the UIS-ED).

Material And Methods: We first developed a version of the questionnaire for Spanish ED situations. Next we assessed the content validity index for each of its items, revised it, and reassessed its face validity to produce a second version, which we then piloted in 20 hospital ED patients. A third revised version was then validated in a population of 320 adults (160 patients and 160 accompanying persons) who attended the ED between November 2015 and September 2016. The 12-item UIS-ED (60 points) was administered by 2 nurses while the patients and accompanying persons were in the ED. We gathered sociodemographic and clinical data as well as the subjects' perception about the information they were given.

Results: The mean (SD) uncertainty score among patients was 29 (11) points. Accompanying persons had a mean score of 36 (13) points. Factorial analysis confirmed the instrument's construct validity, finding that both dimensions of the original Mishel scale (complexity and ambiguity) were present in 6 items each. Factorial analysis explained 60% of the total variance in the patient version and 67% of the variance in the version for accompanying persons. Reliability statistics were good, with Cronbach's α values ranging from 0.912 to 0.938. Split-half reliability statistics ranged from 0.901 to 0.933. Correlations were significant in the analysis of convergent validity.

Conclusion: The UIS-ED questionnaire may prove to be a simple, valid, and reliable way for assessing uncertainty in patients and their accompanying friends or relatives attending Spanish EDs.