ONCE EVERYONE WITH KIDNEY FAILURE IS COUNTED, WHO RECEIVES KIDNEY REPLACEMENT THERAPY – AND WHO DOES NOT?

Since renal registries typically report only the population receiving kidney replacement therapy (KRT: dialysis and transplantation), it is not known know how many people get kidney failure, but do not start treatment, or their demographics. In high-income countries, almost as many may develop kidney failure, but never receive KRT, as those that do start KRT. Age is known to be a major determinant of KRT receipt, perhaps reflecting acquisition of comorbidities and frailty. Knowing i) the factors that influence whether people commence KRT and ii) how the size, demographics, and treatments received by the kidney failure population will change in future, is a priority for service planning. This will be most informative if all people are considered, not just those who receive KRT.

We analysed UK primary care data (CPRD) and linked NHS hospital episode statistics (HES) to identify residents of England aged ≥18 years who developed kidney failure between 2013 and 2020. Kidney failure was coded as incident when eGFR fell <15 for ≥90 days, or upon presence of a treatment code suggesting kidney failure established for ≥90 days. KRT initiation was defined by the presence of a relevant treatment code. Annual incidence rates of kidney failure and KRT uptake were calculated and extrapolated to Office for National Statistics projected population data for England by age and sex for 2024 and 2034. Individuals’ age, sex, socioeconomic status, ethnicity, comorbidities and electronic frailty index were used to model the likelihood of KRT initiation, using a competing risks analysis.

19,129 individuals with incident kidney failure were identified. 11,149 (58%) received KRT before death or end of follow-up. In the adjusted competing risks analysis, female sex (hazard ratio 0.78; 95% confidence intervals - 0.75, 0.81), increasing age (0.36 compared with 70-79 years; 0.34, 0.39), increasing frailty (0.81 for the frailest vs. non-frail; 0.74, 0.88), socioeconomic disadvantage (0.91for the most vs. least deprived; 0.86, 0.97), cerebrovascular disease (0.84; 0.80, 0.89), and dementia (0.44; 0.38, 0.51) were independently associated with a lower likelihood of initiating KRT. 

Those who commenced KRT experienced more inpatient admissions (6 vs 3) and outpatient appointments (15 vs 6) in the last year of life and were more likely to die in hospital (63% vs 46%). 

Annual incidence of kidney failure for males ranged from 2.29 cases per 100,000 population per year (18-19 years age group) to 245.35 per 100,000 (90+ years age group). Equivalent rates in the female population were 1.86 and 119.32 respectively. Extrapolation to the projected 2034 English population predict an increase in the burden of kidney failure – treated both with and without KRT – especially in the older population. 

Just under half of individuals in England who reached kidney failure never started KRT. This heterogenous group includes those who died prematurely before KRT initiation; those whose kidney disease was stable, despite reaching diagnostic thresholds for kidney failure; and others who received conservative kidney management. These individuals are older and frailer than the comparable group who received dialysis or kidney transplants. A substantial increase in the burden of kidney failure is predicted over the next 10 years. By describing this population, our work is a step closer to informing the development of NHS kidney services that meet the needs of the entire kidney failure population.