Use of the Kidney Failure Risk Equation to Determine the Risk of Progression to End-stage Renal Disease in Children With Chronic Kidney Disease

Abstract

Importance: The kidney failure risk equation (KFRE) has been shown to accurately estimate progression to kidney failure in adults with chronic kidney disease (CKD). Use of the KFRE in children with CKD, if accurate, would help to optimize planning for end-stage renal disease (ESRD) care.

Objective: To determine whether the KFRE adequately discriminates the risk of ESRD in children with CKD.

Design, setting, and participants: This retrospective cohort study included 603 children with an estimated glomerular filtration rate of less than 60 mL/min/1.73 m2 in the Chronic Kidney Disease in Children study, a national multicenter observational study. Data were collected from January 1, 2005, through July 31, 2013, and analyzed from September 30, 2016, through September 8, 2017.

Exposures: The primary predictive factors were the 4-variable (age, sex, bedside Schwartz estimated glomerular filtration rate, and ratio of albumin to creatinine levels) and 8-variable (4 variables plus serum calcium, phosphate, bicarbonate, and albumin levels) KFREs, which provide 1-, 2-, and 5-year estimates of the risk of progression to ESRD.

Main outcomes and measures: Time to ESRD. The Cox proportional hazards model was used to examine the association between the KFRE score and time to ESRD. C statistics were used to discriminate ESRD risk by the KFRE, with a value of greater than 0.80 indicating strong discrimination.

Results: Of the 603 children included in the study, 378 were boys (62.7%) and 225 were girls (37.3%); median age at study entry was 12 years (interquartile range, 8-15 years). Median estimated glomerular filtration rate was 44 mL/min/1.73 m2. Four hundred fifty-seven participants (75.8%) had a nonglomerular cause of CKD. Median observation time was 3.8 years (interquartile range, 1.7-6.2 years); 144 (23.9%) developed ESRD within 5 years of enrollment. The 4-variable KFRE scores discriminated risk of ESRD, with C statistics of 0.90, 0.86, and 0.81 for the 1-, 2-, and 5-year risk scores, respectively. Results were similar using the 8-variable equation.

Conclusions and relevance: The KFRE is a simple tool that provides excellent discrimination of the risk of ESRD. Results suggest that the KFRE could be incorporated into the clinical care of children with CKD to aid in anticipatory guidance, timing of referral for transplant evaluation, and planning for dialysis access.

Figure 1.. C Statistics for the 2-Year 8-Variable Kidney Failure Risk Equation by Patient Characteristic

Error bars indicate 95% CI. C statistics and 95% CIs closer to 1.00 indicate better discrimination. CKD indicates chronic kidney disease.

Figure 2.. Estimated vs Observed Probability of End-stage Renal Disease (ESRD) at 2 Years by Risk Group

Data represent the median estimated Kidney Failure Risk Equation (KFRE) scores in each tertile of ESRD risk and the actual percentage of the cohort (Kaplan-Meier estimate) who developed ESRD at 2 years. Estimated risk group 1 corresponds to participants with a 2-year KFRE score of less than 2.6%; risk group 2, KFRE scores of at least 2.6% but less than 13.2%; and risk group 3, KFRE risk score of at least 13.2%.