Differences Between Cystatin C- and Creatinine-Based Estimated Glomerular Filtration Rate and Association with Mortality and Cardiovascular Events: Results from Three Cohorts of Adults with Diabetes.

BACKGROUND AND HYPOTHESIS:To explore the association between the differences between cystatin C- and creatinine-based estimated glomerular filtration rate (eGFRdiff) with the risk of mortality and cardiovascular (CV) events in individuals with diabetes. METHODS:Three prospective cohorts analyzed data of adults with diabetes from the Incident, Development, and Prognosis of Diabetic Kidney Disease (INDEED) study (2016-2017 to 2020) in China, the National Health, Nutrition Examination Survey (NHANES, 1999-2004 to 2019) in the United States, and UK Biobank (UKB, 2006-2010 to 2022). Baseline eGFRdiff was calculated using both absolute difference between cystatin C- and creatinine-based calculations (eGFRabdiff), and the ratio between them (eGFRrediff). Cox proportional hazards regression models were used to investigate the association between eGFRdiff and outcomes including all-cause mortality and incident CV events. RESULTS:A total of 8,129 individuals from the INDEED (aged 60.7±10.0 years), 1,634 from the NHANES (aged 62.5±14.4 years), and 29,358 from the UKB (aged 59.4±7.3 years;) were included. At baseline, 43.6%, 32.4% and 42.1% of participants in the INDEED, NHANES and UKB had an eGFRabdiff value ≥15 ml/min/1.73 m2. During a median follow-up of 3.8 years for the INDEED, 15.2 years for the NHANES, and 13.5 years for the UKB, a total of 430, 936 and 6143 deaths and a total of 481, 183 and 5583 CV events occurred, respectively. Each 1-standard deviation higher baseline eGFRabdiff was independently associated with a lower risk of all-cause mortality and CV events, with hazard ratios (HRs) of 0.77 and 0.82 in the INDEED, 0.70 and 0.68 in the NHANES, and 0.66 and 0.78 in the UKB. Similar results were observed for eGFRrediff. CONCLUSIONS:eGFRdiff represents a marker of adverse events for diabetes among general population. Monitoring both eGFRcys and eGFRcr yields additional prognostic information and has clinical utility in identifying high-risk individuals for mortality and CV events.