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

Abstract 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.