#1637 Diverging trends in kidney replacement therapy (KRT) incidence in Madrid and Catalonia in the past decade
Authors: Abasheva Daria , Garcia-Galan Lucia Cordero , Fernandez-Fernandez Beatriz , Ortiz Alberto 
Published: May 2024

Abstract

Background and Aims
Chronic kidney disease (CKD) is one of the fastest growing global causes of death and the number of persons on KRT is increasing. A critical assessment of current clinical practice across regions may identify best clinical practice, providing a benchmark to improve outcomes. Given the long life expectancy in Spain and its high proportion of the population over 65 y/o, analysis of Spanish data may provide insight for the future for other European countries. Catalonia (Cat) and Madrid (Mad) are two of the most populated Spanish Autonomous Communities, have similar life expectancy (above 83 years) and GDP per capita, and together account for 30% of Spanish population and 38% of GDP. The aim was to set the basis for benchmarking in CKD care and KRT initiation by comparing the evolving KRT incidence of two representative Spanish Autonomous Communities.

Method
We compared the KRT incidence in Cat and Mad from 2012 to 2021, using data from European Renal Association (ERA) Registry annual reports and the Spanish Instituto Nacional de Estadistica's (INE) census.

Results
From 2012 to 2021, the incidence of KRT (day 1) adjusted for age and sex increased by 69.7 pmp (59% increase) in Cat (from 118.7 to 188.4 pmp) and by 14.2 pmp (12% increase) in Mad (from 115.5 to 129.7 pmp). The differential incidence of KRT between Cat and Mad increased from 3.2 to 58.7 pmp, i.e., 1734% increase (Fig. 1A). As a result, the incidence of KRT was 45% higher in Cat than in Mad in 2021 (up from 3% higher in 2012). During the same period, the median age to start KRT increased from 67.0 to 69.6 years (2.6 years, 3.9%) in Cat and from 66.1 to 66.9 years (0.8 years, 1.2%) in Mad.
Median age at KRT initiation in 2021 was 3 years older in Cat in both men (Cat 70.0 (58.4-77.8), Mad 67.3 (56.9-76.2)) and women (Cat 69.0 (58.4-77.2), Mad 66.1 (51.7-75.8)). In subgroup analysis by age and sex, the largest difference in KRT incidence in 2021 was observed for women and for those aged 75+ years: Cat/Mad KRT incidence (pmarp) ratio was 1.79 in women 75+, 1.62 in men 75+, 1.49 in women &lt;75 y/o, 1.34 in men &lt;75 y/o (Fig. 1B). The gap between Cat and Mad increased progressively with age in both men and women and the slope was steeper for women.
The contribution of diabetes to the overall incidence of KRT ranged from 16.8% to 23.2% in Cat and from 24.3% to 29.0% in Mad between 2012 and 2021, remaining grossly stable or decreasing slightly over time. For most causes, the incidence adjusted for age and sex in Cat and Mad was similar, with largest differences observed for unknown cause (the most common cause in Cat: Cat 45.9 pmp, Mad 7.9 pmp) and missing (the 3rd most common cause in Cat after unknown and diabetes: Cat 25.4 pmp, Mad 0) (Fig. 1C). Together, unknown and missing causes of CKD accounted for 38.1% of incident KRT cases in Cat in 2021.
Pre-emptive transplantation was 3-fold more common in Cat in 2021 (7.6% vs 2.7%), while incidence of haemodialysis and peritoneal dialysis were similar (Fig. 1D).

Conclusion
In conclusion, trends for KRT incidence differed for two Autonomous Communities from the same country, broadly comparable in terms of population, life expectancy and GDP. The incidence of KRT was higher in Catalonia, and the gap increasing over time, especially among the elderly and older women, with unknown cause of CKD being the leading cause of incident KRT. An in-depth analysis of the drivers of these differences may bring interesting insight into best practice for CKD prevention, treatment to slow CKD progression and prescription and initiation of KRT.