Cohort Study: The impact of rare kidney diseases on kidney failure and survival rates in the UK’s RaDaR cohort

Study Design and Population: This cohort study utilized data from the UK National Registry of Rare Kidney Diseases (RaDaR), encompassing 27,285 participants aged 0-96 years with 28 types of rare kidney diseases, recruited from 108 renal care facilities across the UK. The primary outcomes assessed were the cumulative incidence of mortality and kidney failure, compared with those of a general population with chronic kidney disease (CKD).

Main Findings: Over a median follow-up of 9.6 years, participants with rare kidney diseases exhibited a significantly higher 5-year cumulative incidence of kidney failure (28%) compared to the broader UK CKD population (1%, p<0.0001). However, they also showed better survival rates, with a standardized mortality ratio of 0.42. There was considerable variability in median ages at kidney failure and death, time from dialysis start to death, and time from diagnosis to reaching specific eGFR thresholds among different rare diseases.

Implications for Practice: This study highlights the distinct trajectory of rare kidney diseases compared to more common forms of CKD, with higher rates of kidney failure but improved survival outcomes. These findings emphasize the over-representation of patients with rare kidney diseases in kidney replacement therapy cohorts and underscore the urgent need for targeted therapeutic interventions. Addressing this unmet need could significantly reduce the demand for long-term kidney replacement therapy, benefiting patients and easing healthcare system burdens.

Reference

Wong K, Pitcher D, Braddon F, Downward L, Steenkamp R, Annear N, et al. (2024). Effects of rare kidney diseases on kidney failure: a longitudinal analysis of the UK National Registry of Rare Kidney Diseases (RaDaR) cohort. The Lancet, 395(10223), P1234-P1245. DOI: https://doi.org/10.1016/S0140-6736(23)02843-X. Access the study here: Link