Kidney Failure Risk Equation and Patterns of Healthcare Resource Utilization

In patients with chronic kidney disease (CKD), as kidney function declines the costs of care increase rapidly due, in part, to higher rates of hospitalizations and visits to the emergency department. The approximately 10% to 15% of the population affected by CKD account for 20% of healthcare costs. Patients with CKD commonly experience comorbid conditions such as diabetes mellitus and congestive heart failure, contributing additional burden to the cost of care.

Costs of care for patients with kidney failure requiring dialysis are exponentially higher than for patients with CKD. In addition, patients on dialysis struggle to remain employed, creating additional burden on society.

The kidney failure risk equation (KFRE) was developed in 2011 and is an accurate predictor of the risk of kidney failure requiring dialysis in patients at risk of progression to kidney replacement therapy. The equation has been validated in several populations, however, according to Bhanu Prasad, MD, FRCPC, and colleagues, there are few data available on the ability of the KFRE to predict healthcare and resource utilization in patients with CKD and estimated glomerular filtration rate (eGFR) of 15 to 59 mL/min/1.73 m2.

The researchers hypothesized that it could be useful if the KFRE can help identify patients with low-cost/nominal resource-intensive treatment from those with high-cost/resource-intensive treatment. Such identification could help outpatient multidisciplinary care-based kidney clinics determine patient management and resource allocation. The research team conducted a retrospective cohort study to examine the association between the risk of progression by KFRE and resource utilization (hospitalizations, physician visits, and drug usage) and associated costs in the setting of a universal healthcare system. Results were reported in the Clinical Journal of the American Society of Nephrology [2022;17(1):17-26].

The cohort included adults with CKD and eGFR of 15 to 59 mL/min/1.73 m2 enrolled in multidisciplinary clinics in the province of Saskatchewan, Canada. Data were collected from January 1, 2004, to December 31, 2012; patients were followed for 5 years (until December 2017). Patients were stratified by eGFR and risk of progression; the groups were compared with regard to the number and cost of hospital admissions, physician visits, and prescription drugs.

A total of 1794 patients with eGFR ranges of 60 to 89, 30 to 59, 15 to 29, and <15 mL/min/1.73 m2 were referred to CKD clinics in Saskatchewan during the study period. Following application of inclusion and exclusion criteria, the final CKD cohort included 1003 patients with eGFR of 30 to 59 mL/min/1.73 m2 (n=529) or 15 to 29 mL/min/1.73 m2 (n=474). Median follow-up was 5 years in both groups.

Mean age in the overall cohort was 71 years and 57% were men (n=570); 75% of patients were ≥65 years of age. In the 30 to 59 mL/min/1.73 m2 eGFR group, 59% (n=311), 28% (n=150), and 13% (n=68) were in low-, medium-, and high-risk categories by KFRE, respectively. Among patients in the group with eGFR 15 to 29 mL/min/1.73 m2, 58% (n=275), 18% (n=86), and 24% (n=113) were in low-, medium-, and high-risk KFRE categories, respectively.

At the end of 5 years of follow-up, of the patients in the eGFR 30 to 59 mL/min/1.73 m2 group, 4% of the low-risk subgroup, 11% of the moderate-risk subgroup, and 26% of the high-risk group had progressed to kidney failure requiring dialysis (P<.001). During the 5-year follow-up period, 31% at low risk, 36% at medium risk, and 28% at high risk for progression to kidney failure died.

Of patients in the eGFR 15 to 29 mL/min/1.73 m2 group, 7% at low risk, 17% at medium risk, and 48% at high risk of kidney failure progressed to dialysis over 2 years (P<.001). During the 2 years, 15% at low risk, 21% at moderate risk, and 16% at high risk of progression to kidney failure died.

After controlling for potential confounders, in the group with eGFR 30 to 59 mL/min/1.73 m2, patients in the high-risk subgroup utilized 50% more hospital-based services (inpatient and day surgeries) than patients in the low-risk subgroup over the 5-year study period (P=.006). High-risk patients also had 52% more higher utilization of physician services compared with low-risk patients. There were no statistically significant differences across the risk groups in drug dispensations. Findings were similar in the group with eGFR 15 to 29 mL/min/1.73 m2: high-risk patients consumed 72% more hospital services and 2.2 times more physician services than patients in the low-risk group (both P<.001). There were no differences in drug dispensations.

In the group with eGFR 15 to 29 mL/min/1.73 m2, comparing patients at high risk for progression to kidney failure with those at low risk of progression, the costs of hospital admissions, physicians visits, and drug dispensations over the 5-year study period were (Canadian dollars): $89,265 versus $48,374 (P=.008); $23,423 versus $11,231 (P<.001), and $21,853 versus $16,757 (P=.01), respectively.

The costs for hospital admissions, physician services, and drug dispensations in the group with eGFR 30 to 59 mL/min/1.73 m2 for high-risk versus low-risk patients were $55,944 versus $36,740 (P=.10), $13,414 versus $10,370 (P=.08), and $20,394 versus $14,902 (P=.02), respectively.

Limitations to the study findings cited by the authors included the possible lack of generalizability outside of the Canadian healthcare system and the lack of data on variables such as socioeconomic characteristics and health behaviors.

In conclusion, the researchers said, “In our study of patients with CKD referred to multidisciplinary CKD clinics, KFRE, designed to predict the risk of dialysis in patients with CKD, helps identify patients with higher health resource utilization and healthcare costs compared with those with lower health resource use. Integration of KFRE in risk-based treatment pathways that guide the intensity of CKD care may improve health system and patient outcomes.”

Takeaway Points

  1. Researchers in Canada conducted a retrospective cohort study to determine patterns of healthcare utilization in patients with chronic kidney disease (CKD) on the basis of their risk of progression to kidney failure as determined by the kidney failure risk equation (KFRE).
  2. Patients with CKD with estimated glomerular filtration rate (eGFR) of 30-59 mL/min/1.73 m2 at high risk for progression to kidney failure utilized 50% more hospital-based services than did those with low risk for progression.
  3. In the group of patients with eGFR of 15-29 mL/min/1.73 m2 the costs of hospital admissions, physician visits, and drug dispensations over the study period were higher in the group at high risk of progression compared with those at low risk.