Validation of the kidney failure risk equation (KFRE) to predict kidney failure and guide referrals from primary care for individuals with CKD who also experience multiple long-term health conditions or frailty

Conference:

SAPC ASM 2024 - Bristol

Talk Code:

10B.5

Presenter:

Heather Walker

Twitter:

@h_j_walker

Co-authors:

Juan-Jesus Carrero, Michael Sullivan, Anne-Laure Faucon, Bhautesh Jani, Katie Gallacher, Patrick Mark

Author institutions:

School of Cardiovascular and Metabolic Health, University of Glasgow, Department of Medical Epidemiology and Biostatistics, Karolinska Instituet, Stockholm, School of Health and Wellbeing, University of Glasgow

Problem

An estimated 10-15% of the population have a diagnosis of chronic kidney disease (CKD). Increasing numbers of individuals with CKD will also experience multiple long-term conditions (multimorbidity) and/or frailty. NICE clinical guidelines recommend the use of the kidney failure risk equation (KFRE), to estimate the five-year risk of kidney failure for patients with CKD and to guide referrals from primary care to secondary care kidney clinics. The impact of multimorbidity and/or frailty on the ability of KFRE to predict kidney failure and guide secondary care referral has not been studied.

Approach

This study aimed to validate KFRE in individuals with CKD, with and without multimorbidity and/or frailty, in a research-based cohort (UK Biobank) and a population-based cohort (Stockholm Creatinine Measurements project (SCREAM)). Individuals were included if they had CKD, defined as eGFR<60mL/min/1.73m2, and had available proteinuria measurement at time of testing or within the previous 12 months. Multimorbidity was defined as the presence of two or more long-term conditions in addition to CKD. Frailty was assessed by the Fried frailty phenotype, Rockwood frailty index and laboratory frailty index. The outcome was kidney failure (the need for long-term dialysis or kidney transplantation). KFRE performance at 5-years was assessed using the area under the receiver operating characteristic curve (AUC) for discrimination and calibration curves for calibration.

Findings

We included 24,489 individuals from UK Biobank and 42,902 individuals from SCREAM (mean age 62.8 (SD 5.6) and 70.1 (SD14.1), 54% and 66% female, respectively). In UK biobank, 14,998 individuals had multimorbidity, 8,533 were classed as frail and 6,503 had both multimorbidity and frailty. In SCREAM, 30,147 had multimorbidity, it was not possible to assess frailty in this cohort as frailty measures were not routinely recorded. Overall, there were 312 kidney failure events and 1,471 death events in UK Biobank and 1,098 kidney failure events and 10,152 death events in SCREAM within 5-years.Model performance was consistent across both cohorts in all sub-groups. Discrimination power of KFRE was good in individuals with and without multimorbidity and/or frailty (AUC ≥0.88 across all sub-groups). In all sub-groups calibration plots revealed under-estimation of risk at 5-years. There was a higher cumulative incidence of both kidney failure and death in the multimorbidity and frailty groups, with a prominent increase in risk of death over time compared to the no multimorbidity/frailty groups.

Consequences

KFRE adequately and consistently predicts kidney failure risk in individuals with multimorbidity and/or frailty. Given the high rates of mortality amongst individuals with multimorbidity or frailty, explorations of models that account for competing risk of death is warranted. Further work is planned to explore patient and healthcare professionals’ perspectives of kidney failure risk and the use of KFRE in individuals with CKD and multimorbidity and/or frailty to guide care and policy.

Submitted by:

Heather Walker

Funding acknowledgement:

HW is a fellow on the Multimorbidity Doctoral Training Programme for Health Professionals, which is supported by the Wellcome Trust, grant number 223499/Z/21/Z.