Psychometric evaluation of the Persian version of the Doloplus-2 (P-Doloplus-2) scale in elderly with dementia

BACKGROUND/AIM: A scale for behavioural pain assessment is useful for the detection and determination of pain in the elderly with dementia. This study aimed to translate and evaluate the psychometric properties of Doloplus-2 in the elderly with dementia in Iran. MATERIALS AND METHODS: In this methodological study, after translation and evaluating the face and content validity of Doloplus-2, 100 elderly people were selected by the convenience sampling method in Kashan, 2018–2019. Exploratory factor analysis, convergent validity, and known-groups comparison were applied to determine construct validity. Reliability was also assessed through internal consistency, equivalence, and stability methods were used. The ceiling and floor effects were also examined. Data were analyzed using the SPSS-v16 and via Mann-Whitney U test, Cronbach’s alpha, Spearman-Brown, and intraclass correlation coefficient (ICC). RESULTS: The scale’s content validity index was 0.95%, and the item impact of each item was above 1.5. Factor analysis identified 2 “social-functional” and “conventional subjective-objective” factors in scale that altogether were able to explain 76% of the total variance. The results revealed that P-Doloplus-2 could discriminate between the 2 groups of elderly with and without known chronic painful diseases (P < 0.0001). There was a significant positive correlation between P-Doloplus-2 and PACSLAC-II-IR scores (r = 0.878, P < 0.0001). Cronbach’s alpha, ICC, and standard error of measurement for the scale were 0.950, 0.864, and ± 1.759, respectively. The frequency of minimum and maximum possible score of scale was less than 15%. CONCLUSION: The Persian version of Doloplus-2 can be considered as a valid and reliable scale for pain assessment in the elderly with dementia.