Mortality risk by kidney function trajectories in an ethnically diverse type 2 diabetes cohort

Abstract Background The impact of kidney function decline before chronic kidney disease (CKD) on mortality, especially across ethnic groups, is unclear. We examined estimated glomerular filtration rate (eGFR) trajectories and their association with mortality in an ethnically diverse type 2 diabetes cohort. Methods We analysed data from 14,489 adults [mean age 63.2 (SD ± 12.2), 52% male with type 2 diabetes in South London between 2004-2018. All had baseline eGFR ≥45 ml/min/1.73m² and ≥2 annual eGFR readings over two years. Group-based modelling identified four eGFR patterns, including a rapid decline group (eGFR fall ≥2 ml/min/year). Mortality was linked to national records. Survival in the rapid decline group was analysed using Kaplan-Meier and Cox models, adjusted for baseline age, gender, HbA1c, blood pressure, BMI, albuminuria, diabetes duration, cholesterol, and CKD stage. Results There were 3,054 deaths during follow-up, over 70% in rapid or moderate decline groups. Mortality was lowest (1.5-5%) in those with stable function. In the rapid decline group, adjusted Cox models showed lower mortality in Black (HR = 0.66; 95% CI: 0.57-0.77; n = 281), Asian (HR = 0.73; 95% CI: 0.59-0.91; n = 98), Mixed (HR = 0.61; 95% CI: 0.42-0.89; n = 30), and Other (HR = 0.63; 95% CI: 0.44-0.88; n = 35) groups vs. White (n = 660). Older age, male sex, higher HbA1c, and raised systolic/diastolic blood pressure were associated with mortality. Conclusions Rapid eGFR decline is a stronger and more consistent predictor of mortality in type 2 diabetes than ethnicity. White participants in the rapid decline group had the highest risk. Monitoring early eGFR change /trajectories may support early risk detection, and guide targeted care. Key messages • Kidney function decline predicts death in type 2 diabetes better than ethnicity and early detection enables targeted, life-saving interventions. • Routine monitoring of eGFR patterns in diabetes care can reduce premature deaths and support more equitable, risk-based public health responses.