#1137 Association between cognitive function, depressive symptoms and quality of life in older patients with severely reduced GFR and kidney failure

Abstract Background and Aims Impaired cognitive function and reduced health-related quality of life (HRQoL) are common in older patients with chronic kidney disease (CKD) with severely reduced GFR and kidney failure. Older patients with CKD often regard HRQoL as a health priority, but it is unknown whether cognitive function associates with HRQoL and whether depressive symptoms mediate this association. We therefore aim to examine the association between cognitive function and HRQoL, and explore the mediating role of depressive symptoms. Method Patients aged 65 years and older with an eGFR between 20 and 10 mL/min/1.73 m2 participating in the ongoing DIALysis or not: Outcomes in older kidney patients with GerIatriC Assessment (DIALOGICA) study were included. Cognitive function, depressive symptoms and HRQoL were assessed using the Montreal Cognitive Assessment (MoCA), Geriatric Depression Scale (GDS-15) and Twelve-Item Short Form Health Survey (SF-12) questionnaire, respectively. The SF-12 yields a Mental Component Summary (MCS) score and Physical Component Summary score (PCS). We created a diagram of the hypothesized direct and indirect pathways between cognition and HRQoL, with depressive symptoms as the purported mediator (Fig. 1). We used cross-sectional multivariable linear regression analyses to examine the association between cognitive function and both mental and physical HRQoL, and multivariable mediation analyses to explore the role of depressive symptoms. Results In total, 403 patients were included with a mean age of 76.5 years, with a standard deviation (SD) of 5.8 and a mean eGFR of 14.5 mL/min/1.73 m2 (SD 3.0). A majority of patients were male (71.5%). Cognitive function associated significantly with mental HRQoL (adjusted β 0.30, 95% confidence interval (CI) 0.05; 0.55, p 0.021), but not with physical HRQoL (adjusted β 0.18, 95% CI −0.09; 0.44, p 0.20). The mediation effect of depressive symptoms between cognitive function and MCS remained significant after adjustment (indirect effect 0.15, 95% CI 0.04; 0.26). Thus, lower cognitive function was associated with lower mental HRQoL, which was partly mediated by corresponding increases in depressive symptoms. Conclusion Cognitive function is associated with mental HRQoL, but not with physical HRQoL in older patients with severely reduced GFR and kidney failure. This association is partially mediated by depressive symptoms. These findings underline the importance of screening for cognitive impairment and depressive symptoms in this population and may increase the understanding of what potentially affects HRQoL. As HRQoL is seen as a health priority, further research should explore whether cognitive interventions or treatment of depressive symptoms result in improvement of HRQoL in this population.