The relationship between chronic kidney disease progression and disease cost of stage 3-5 chronic kidney disease patients according to the "Kidney Failure Risk Equation" classification

In the management of chronic kidney disease (CKD), treatment decisions are often based on estimated glomerular filtration rate (eGFR) or albuminuria. In recent years, new models have been developed to predict the risk of progression to end-stage kidney disease in stage 3-5 CKD patients. These 4-variable and 8-variable equations, called "Kidney Failure Risk Equation" (KFRE), include age, gender, eGFR, urine albumin-creatinine ratio, serum calcium, serum phosphorus, serum bicarbonate and serum albumin parameters. The aim of this study is to predict 2- and 5-year progression by performing risk analyzes according to KFRE in patients with a diagnosis of CKD, and to examine the possible relationship between the risk groups and the use of resources as well as the hospital costs. Among total of 822 patients [415 (50.5%) women and 407 (49.5%) men], 635 were diagnosed with stage 3 (77.3%) and 187 (22.7%) were diagnosed with stage 4 CKD. The 5-year End-Stage Kidney Disease Free Survival (ESKD-FS) rate in stage 3 patients is 95.7±1.1% in low-risk patients, 89.7±2.7% in intermediate-risk patients, 64.2±5% in high-risk patients, according to the 4-variable KFRE classification (p<0.001). In stage 4 patients, the 2-year ESKD-FS) rate was found to be 100% in low-risk patients, 92.3±3.7% in medium-risk patients, and 64±5.1% in high-risk patients according to the 4-variable KFRE classification (p<0.001). According to the 8-variable KFRE classification, the 5-year ESKD-FS rate in stage 3 patients was 98±0.9% in low-risk group, 82.6±3.4% in medium-risk group, and 67.6±5.6% in high-risk group (p<0.001). According to the same classification, the 2-year ESKD-FS rate in stage 4 patients was 97.7±2.3% in the low-risk group, 96.1±2.7% in the medium-risk group, and 60.2±5.4% in the high-risk group (p<0.001). In both stages, as the risk level increased according to the 4-variable and 8-variable Kidney Failure Risk Equation classification, an increase in the rates of invasive procedures such as coronary angiography, non-cardiac angiography, surgery, kidney biopsy, arteriovenous fistula creation and tunneled dialysis catheter insertion was observed. It was shown that the median annual outpatient and hospitalization costs increased as the risk group increased in stage 3 CKD patients according to the 4-variable KFRE classification (p=0.025 and p=0.045, respectively). In conclusion, 4-variable and 8-variable KFRE risk classifications are very useful in indicating progression to end-stage kidney disease in stage 3 and stage 4 CKD patients. In addition, the mentioned risk classifications can be used effectively in predicting hospital resources use and costs.