The association between coding for chronic kidney disease and kidney replacement therapy incidence at CCG-level in England: an ecological study

Background With ageing of the population both prevalence of chronic kidney disease (CKD) and incidence of kidney replacement therapy (KRT) are rising. Existing research suggests that Read-coding for CKD in those affected is associated with better implementation of recommended care and fewer hospitalisations for heart failure.

Aim To investigate whether coding for CKD is associated with regional KRT incidence in England.

Design & setting This is an ecological study using the clinical commissioning groups (CCG) in England as geographical units.

Method KRT incidence rates were calculated using UK Renal Registry (UKRR) data from 01/2019 to 12/2021. Data on the percentage of uncoded CKD patients (PUCP) who had laboratory evidence of CKD but lacked a diagnostic code were obtained from the CVDPREVENT Audit, a national audit that extracts routinely held general practitioner data. Data on confounders and acute kidney injury (AKI) mortality as a marker for population frailty were obtained from CVDPREVENT and the UKRR, respectively. Poisson models assessed the association between PUCP and KRT incidence.

Results After adjusting, the PUCP was non-linearly associated with KRT incidence, with the CCGs in the lowest PUCP quintile having a lower KRT incidence than the others. There was evidence that this association was more pronounced in CCGs with high AKI mortality compared to CCGs with low AKI mortality.

Conclusion At the geographical level in England, the data suggests that the prevalence of not having formally diagnosed CKD is non-linearly associated with a higher KRT incidence rate, especially in areas with a high AKI mortality.