MRI-defined versus clinically-defined vascular depression; comparison of prediction of functional disability in the elderly

Background: We compared the validity of models of subcortical ischemic depression (SID) and depression-executive dysfunction syndrome (DED) in predicting functional disability in the elderly. Methods: We obtained data from elderly Korean subjects (n = 1356) aged 60 years or older at baseline from the CREDOS study from November 2005 to July 2014. A generalized estimating equation (GEE) model was constructed to measure functional disability using instrumental activity of daily living as a primary outcome. A risk factor of interest was SID and DED evaluated by a visual rating scale of deep white matter hyperintensity in MRI, Stroop test and Geriatric Depression Scale (GDS) score. Receiver-operating-characteristic plots and area under the curve (AUC) test were applied to examine the difference of the two definitions of vascular depression with predicted values of functional disability outcome. Results: The mean (SD) follow-up duration of the participants was 1.7 (0.9) years. The GEE model showed that presence of SID at baseline predicted functional disability compared to non-depressed subjects (GDS score: Odds ratio [OR] 1.76; 95% CI 1.23, 2.53; p = 0.002). The association was also statistically significant among the DED group (OR 1.48; 95% CI 1.15, 1.92; p = 0.003). There were no significant differences in predicting functional disability (95% CI: -0.003 to 0.009, p = 0.366) according to AUC differences between SID and DED. Conclusions: The results will be useful in evaluating the cardinal features of the vascular depression hypothesis in predicting functional disability. (C) 2016 Elsevier Ireland Ltd. All rights reserved.