Multiple-Serial Mediating Effects Of Activity Of Daily Living And Depression Between PD Severity/Cognitive Function And Quality Of Life In Patients With Parkinson's Disease

Objective:To explore whether severity and cognition can aggravate depression by reducing activity of daily living separately,thus reducing the quality of life(QOL)among patients with Parkinson's disease(PD),and to explore further whether there is a difference between the mechanisms of the physical health and mental health in QOL.Methods:Using the cross-sectional study,150 outpatients and inpatients with PD from Department of Neurology in the First Hospital of Shanxi Medical University were investigated.Besides collecting their basic information,such as gender,age,smoking,drinking,we also interviewed the patients with scales including modified Hoehn and Yahr Stage(H&Y),Mini-Mental State Examination(MMSE),Unified Parkinson's Disease Rating Scale(UPDRS),Geriatric Depression Scale(GDS)and The Mos 36-item Short Form Health Survey(SF-36).Multiple mediation models were developed with PD severity and cognitive function as the independent variables,the patient's mental health and physical health as the dependent variables,and activities of daily living and depression as mediators.We applied Monte Carlo expansion method to analyze the multiple mediating effects of the activity of daily living and depression.Path analysis and multiple mediation effects analysis were performed using Amos 20.0 software and the R 3.5.1 software RMediation package,respectively.The statistical test level was 0.05.Results:The scores for PD severity,cognitive function,activities of daily living,depression,physical health and mental health were significantly correlated with each other(P < 0.01).Mediating effect of PD severity through activities of daily living and depression on mental health was statistically significant(b1b2b3=-1.362;95% CI:(-2.135,-0.726)),but direct effect of PD severity on mental health was not statistically significant(c?=-0.386,p=0.548);Mediating effect of PD severity through activities of daily living and depression on physical health was statistically significant(b1b2b3=-0.306;95% CI:(-0.669,-0.026)),and direct effect of PD severity on physical health was also statistically significant(c?=-3.170,p<0.001);Mediating effect of cognitive function through activities of daily living and depression on mental health was statistically significant(b1b2b3=0.432;95% CI:(0.256,0.645)),but direct effect of cognitive function on mental health was not statistically significant(c?= 0.157,p=0.313);Mediating effect of cognitive function through activities of daily living and depression on physical health was statistically significant(b1b2b3=0.111;95% CI:(0.025,0.219)),and direct effect of cognitive function on physical health was also statistically significant(c?= 0.643,p<0.001).The results showed that activities of daily living and depression were two multiple-serial mediation variables of PD severity and cognition affecting the quality of life of patients,and PD severity and cognition can aggravate the depression of patients by reducing activities of daily living,and thus lead to the decline of mental health and physical health of patients.In addition,the results also showed that partial mediation of activities of daily living and depression was found in PCS models,while completely mediation of activities of daily living and depression was found in MCS models.Conclusion:Activities of daily living and depression were two multiple-serial mediation variables of PD severity and cognition affecting the patients QOL,with PD severity worse or cognitive function decline,then the activities of daily living decline,and the patient's psychological status seriously affected,and even leading to depression,which in turn affects the patients QOL.Therefore,we can improve the patients QOL by improving the activities of daily living of PD patients and reducing the symptoms of depression.PD severity and cognition have an impact on patients' mental health through activities of daily living and depression completely,but the influence on the physical health of patients may has other potential mechanisms in addition to the path.Therefore,different measures are needed to combine to make reasonable rehabilitation for psychological and physical functions in the treatment of patients with PD.