Main and moderated effects of multimorbidity and depressive symptoms on cognition

Abstract

Objective: Multimorbidity, or the occurrence of two or more chronic conditions, is a global challenge, with implications for mortality, morbidity, disability, and life quality. Psychiatric disorders are common among the chronic diseases that affect patients with multimorbidity. It is still not well understood whether psychiatric symptoms, especially depressive symptoms, moderate the effect of multimorbidity on cognition.

Methods: We used a large (n=2,681) dataset to assess whether depressive symptomatology moderates the effect of multimorbidity on cognition using structural equation modelling.

Results: It was found that the more depressive symptoms and chronic conditions, the worse the cognitive performance, and the higher the educational level, the better the cognitive performance. We found a significant but weak (0.009; p = 0.04) moderating effect.

Conclusion: We have provided the first estimate of the moderating effect of depression on the relation between multimorbidity and cognition, which was small. Although this moderation has been implied by many previous studies, it was never previously estimated.

Keywords: Multimorbidity; aging; epidemiology; structural equation modeling.

Figure 1. Structural equation model. The circle represents the latent variable (cognitive performance) and boxes are the measured variables. Straight arrows represent the direction of the relationship. The values are estimated coefficients. Dashed arrows are negative coefficients. The indicators in the left column were allowed to correlate, but we omitted the arrows in the interest of clarity. χ²₍₂₎ = 20.12, p < 0.001; comparative fit index = 0.993; Tucker-Lewis index = 0.926; root mean squared error of approximation = 0.058. Not shown, moderation between Hospital Anxiety and Depression Scale-Depression Subscale (HADS-D) and multimorbidity (MM): 0.009 (p = 0.04). MMSE = Mini-Mental State Examination.