Effects of Six Sigma methodology on depression and anxiety of patients with end-stage renal disease

BACKGROUND Depression and anxiety are common psychological conditions in end-stage renal disease (ESRD) patients and contribute to poor quality of life and increased mortality. Six Sigma methodology is a novel method of hospital management. The aim of the present study was to determine whether Six Sigma methodology could reduce the incidence of depression and anxiety in ESRD patients. METHODS ESRD patients undergoing hemodialysis from March 2018 to February 2020 were enrolled in the study. They were divided into the control group or study group according to whether they received conventional nursing care or Six Sigma methodology, respectively. Data on patients' demographic characteristics were retrospectively collected. The conditions of depression and anxiety were assessed by the Self-Rating Depression Scale and the Self-Rating Anxiety Scale, and the severity of depression and anxiety was defined according to the scores of the scales. Univariable and multivariable logistic regression analyses were used to determine the risk factors of depression and anxiety at discharge in ESRD patients and the effects of Six Sigma methodology on them. RESULTS A total of 251 patients were retrospectively enrolled in the study, with 112 patients in the control group and 139 patients in the study group. There were no significant differences in the collected demographic characteristics between the two groups. Six Sigma methodology was shown to relieve mild and moderate depression and anxiety at discharge; however, severe depression and anxiety was hardly affected by Six Sigma methodology. The results from multivariable logistic regression analysis identified Six Sigma methodology as an important protective factor of psychological conditions at discharge. Depression and anxiety status at admission and older age are also independent risk factors for anxiety at discharge in ESRD patients. Marital status may also play a role in the incidence of depression. CONCLUSIONS Six Sigma methodology is significantly useful to reduce the incidence of mild and moderate depression and anxiety at discharge, and should be extended to improve psychological conditions in ESRD patients.