Socioeconomic Inequities in Early Kidney Care Concentrate at Late Initial Clinical Detection Rather Than Planned Care: A Population-Based Study

Introduction Socioeconomic inequities in chronic kidney disease (CKD) outcomes are recognised and greater at early stages, but where exactly inequities arise within early care remains unclear. This distinction is critical: if disparities occur before clinical recognition, strategies focused on management after diagnosis may have limited impact. Methods We conducted a population-based cohort study linking healthcare and Census data for adults in North-East Scotland, 2011-2020. We examined sequential components of early kidney care from initial clinical detection (eGFR <60 mL/min/1.73 m^2). Exposures were household and neighbourhood deprivation and living circumstances (rurality, living alone, mental health). Components of early kidney care were: prior surveillance; presentation (including late/unmonitored); confirmation/monitoring; treatment initiation; and unplanned emergency care. Adjusted risk ratios were estimated using modified Poisson models. Mortality was assessed up to 10 years using Cox regression with separate short-term (<1 year) and long-term estimates. Results Among 44,252 individuals, inequities were most pronounced at initial clinical detection. Individuals from deprived households were more likely to present late (adjusted RR 1.69, 95% CI 1.48-1.93). Inequities in planned monitoring after presentation were less evident (RR 1.00, 0.95-1.05). Urine albumin testing was infrequent among those with cardiovascular risk factors. Late presentation was also associated with increased mortality (adjusted HR 1.78, 1.70-1.87), persisting beyond the first year. Conclusions Socioeconomic inequities in CKD are greatest at or before initial clinical detection, with late presentation a measurable indicator. Emphasis on primary care monitoring and prescribing is unlikely to reduce disparities if early detection and awareness are not also addressed.