Construct validity of the Brazilian version of the Medical Outcomes Study Social Support Survey (MOS-SSS) in a sample of elderly users of the primary healthcare system

Objective: To assess the psychometric properties of the Medical Outcomes Study Social Support Survey (MOS-SSS) considering a sample of elderly users of the primary healthcare facilities of Ribeirao Preto, state of Sao Paulo, southeast Brazil. Methods: The MOS-SSS is a widely used measurement of social support in different contexts, consisting of 19 items with answer categories that range on a 7-point rating scale. Data collection regarding the psychometric properties of the MOS-SSS was performed in a stratified sample of elderly users of primary healthcare facilities of Ribeirao Preto. Data were collected at five district basic health units located in the city through face-to-face interviews. Polychoric correlation matrix and exploratory (EFA) and confirmatory (CFA) factor analyses were performed. Results: A total of 357 elderly subjects aged 60 years or older participated in the study (62.7% females). According to the polychoric correlation matrix, higher coefficients of correlation (> 0.90) were detected among 12 pairs of items and grouped into four factors, as suggested for EFA. The results of the CFA confirmed the construct validity of the four-factor structure of the MOS-SSS when applied to our sample, as well as the stability of this model in distinct subsamples. Conclusion: The four-factor structure of the MOS-SSS was found to be suitable and presented adequate construct validity for the assessment of social support in elderly users of primary healthcare facilities.