External Validation of the Kidney Failure Risk Equation Among Urban Community-Based Chinese Patients With CKD

Rationale & Objective

The Kidney Failure Risk Equations have been proven to perform well in multinational databases, whereas validation in Asian populations is lacking. This study sought to externally validate the equations in a community-based chronic kidney disease cohort in China.

Study Design

A retrospective cohort study.

Setting & Participants

Patients with and estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² dwelling in an industrialized coastal city of China.

Exposure

Age, sex, eGFR, and albuminuria were included in the 4-variable model, whereas serum calcium, phosphate, bicarbonate, and albumin levels were added to the previously noted variables in the 8-variable model.

Outcome

Initiation of long-term dialysis treatment.

Analytical Approach

Model discrimination, calibration, and clinical utility were evaluated by Harrell’s C statistic, calibration plots, and decision curve analysis, respectively.

Results

A total of 4,587 participants were enrolled for validation of the 4-variable model, whereas 1,414 were enrolled for the 8-variable model. The median times of follow-up were 4.0 (interquartile range: 2.6-6.3) years for the 4-variable model and 3.4 (2.2-5.6) years for the 8-variable model. For the 4-variable model, the C statistics were 0.750 (95% CI: 0.615-0.885) for the 2-year model and 0.766 (0.625-0.907) for the 5-year model, whereas the values were 0.756 (0.629-0.883) and 0.774 (0.641-0.907), respectively, for the 8-variable model. Calibration was acceptable for both the 4-variable and 8-variable models. Decision curve analysis for the models at the 5-year scale performed better throughout different net benefit thresholds than the eGFR-based (<30 mL/min/1.73 m²) strategy.

Limitations

A large proportion of patients lack albuminuria measurements, and only a subset of population could provide complete data for the 8-variable equation.

Conclusions

The kidney failure risk equations showed acceptable discrimination and calibration and better clinical utility than the eGFR-based strategy for incidence of kidney failure among community-based urban Chinese patients with chronic kidney disease.

Plain-Language Summary

Accurate and reliable risk evaluation of chronic kidney disease (CKD) prognosis can be helpful for physicians to make decisions concerning treatment opportunity and therapeutic strategy. The kidney failure risk equation is an outstanding model for predicting risk of kidney failure among patients with CKD. However, the equation is lacking validation among Chinese populations. In the current study, we demonstrated that the equation had good discrimination among an urban community-based cohort of patients with CKD in China. The calibration was also acceptable. Decision curve analysis also showed that the equation performed better than a traditional kidney function-based strategy. The results provide the basis for using predictions derived from the kidney failure risk equation to improve the management of patients with CKD in community settings in China.