Reliability and validity of the center for epidemiologic studies depression scale in patients with systemic sclerosis
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Reported rates of depressive symptoms in patients with systemic sclerosis (SSc) are high. No depression assessment tools, however, have been validated for patients with SSc. Our objective was to assess the internal consistency reliability, convergent validity, and structural/construct validity of the Center for Epidemiologic Studies Depression Scale (CES-D) in patients with SSc.
We conducted a cross-sectional, multicenter study of 470 SSc patients. Internal consistency reliability was assessed with Cronbach's alpha and structural/construct validity with confirmatory factor analysis.
Internal consistency reliability was good for the overall CES-D scale (alpha = 0.88) and for its 4 factors (alpha = 0.67-0.88). Correlations of the CES-D total score were -0.73 with mental health, -0.36 with physical health, 0.41 with disability, and 0.44 with pain. The 4-factor model originally found in the general population and validated for patients with rheumatoid arthritis (depressed affect, somatic/vegetative, [lack of] positive affect, and interpersonal factors) fit the data well, as did a second-order version of the same model with an overarching depression factor that loaded onto each of the 4 first-order factors. The 4-factor model fit the SSc data better than alternative models.
Internal consistency reliability and convergent validity were good, the 4-factor structure reported in the general population was replicated, and a second-order model with an overarching depression factor fit well. These findings indicate that the CES-D is a valid and reliable measure of depressive symptoms for patients with SSc.