Development and validation of the dialysis dementia risk score: A retrospective population-based, nested case-control study.

Abstract

BACKGROUND\nDementia is prevalent and underdiagnosed in the dialysis population. We aimed to develop and validate a simple dialysis dementia scoring system to facilitate identification of individuals who are at high-risk for dementia.\n\n\nMETHODS\nWe applied a retrospective nested case-control study design using a national dialysis cohort derived from the National Health Insurance Research Database in Taiwan. Patients aged between 40-80 years were included and 2,940 patients with incident dementia were matched to 29,248 non-dementia controls. All subjects were randomly divided into the derivation and validation sets with a ratio of 4:1. Conditional logistic regression models were used to identify factors contributing to the risk score. The cutoff value of the risk score was determined by Youden s J statistic and the graphic method.\n\n\nRESULTS\nThe dialysis dementia risk score(DDRS) finally included age and ten comorbidities as risk predictors. The C-statistics of the model is 0.71(95% confidence interval(CI):0.70-0.72). Calibration revealed a strong linear relationship between predicted and observed dementia risk(R2 :0.99). At a cutoff value of 50 points, the high-risk patients had approximately 3-fold increased risk of having dementia compared to those with low risk(odds ratio:3.03,95% CI: 2.78-3.31). The DDRS performance, including discrimination(c-statistic:0.71,95% CI:0.69-0.73) and calibration(p-value of Hosmer-Lemeshow test for goodness of fit=0.18), was acceptable during validation. The value of odds ratio(2.82, 95% CI:2.37-3.35) was similar to those in the derivation set.\n\n\nCONCLUSIONS\nThe DDRS system has the potential to serve as an easily accessible screening tool to determine the high-risk groups who deserve subsequent neurological evaluation in the daily clinical practice.