Functional social support: A systematic review and standardized comparison of different versions of the DUFSS questionnaire using the EMPRO tool

BACKGROUND: Functional social support is one of the most established predictors of health, and the Duke-UNC Functional Social Support Questionnaire (DUFSS) is one of the most commonly used instruments to measure this parameter. The objective of this study is to systematically review the available evidence on the psychometric and administration characteristics of the different versions of the DUFSS and perform a standardized assessment though to a specifically designed tool. METHODS: A systematic review was performed in the PubMed/MEDLINE, SCOPUS, WOS and SCIELO databases. All articles that contained information on the development process of the instrument, the psychometric properties and aspects related to its administration were included, without restrictions based on publication date, language, or the version of the questionnaire that was studied. The selection and extraction procedure were carried out by two researchers. The articles finally included were peer-reviewed through a standardised assessment using the Evaluating the Measurement of Patient-Reported Outcomes (EMPRO) tool. PROSPERO registration number: CRD42022342977. RESULTS: A total of 54 articles were identified. After eliminating duplicates and screening articles based on the selection criteria, 15 studies that examined the DUFSS questionnaire resulting in 4 different versions: 3 articles obtained the 8-item version; 11 the 11-item version; and a single article obtained two versions, the 14-item version and the 5-item version. At least 60% of them did so in a young adult population, predominantly female and with a medium-low socio-economic level or with characteristics of social vulnerability. The EMPRO evaluation showed that the 11-item version (54.01 total score) was the only one that had been studied on all recommended attributes and had higher total scores than the other versions: 8 items (36.31 total score), 14 items (27.48 total score) and 5 items (23.81 total score). This difference appears in all attributes studied, with the highest scores in "reliability (internal consistency)" and "validity". CONCLUSIONS: Of the 4 versions identified in the DUFSS questionnaire, the 11-item version was found to be optimal based on the EMPRO standardized tool. Although, a priori, we could prioritise its use in epidemiological studies over the other versions, it should be noted that this version should also be used with caution because there are attributes that have not been studied.