Association of kidney disease index with all‐cause and cardiovascular mortality among individuals with hypertension

BACKGROUND: This study aimed to investigate the association between a novel kidney disease index (KDI), which combines information from both estimated glomerular filtration rate (eGFR) and urinary albumin‐to‐creatinine ratio (uACR), and all‐cause and cardiovascular disease (CVD) mortality among individuals with hypertension. METHODS: We analyzed data from 19 988 adults with hypertension who participated in the National Health and Nutrition Examination Survey from 1999 to 2018. Mortality outcomes were determined by linking to National Death Index records through December 31, 2019. Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals for all‐cause and CVD mortality. RESULTS: Baseline KDI levels were positively associated with glucose, insulin resistance, hemoglobin A1c, triglycerides, and C‐reactive protein (p value for trend <.05). During a follow‐up period of 179 859 person‐years, a total of 5069 deaths were documented, including 1741 from cardiovascular causes. After multivariable adjustment, each standard deviation increment in KDI level was associated with a 27% increased risk of all‐cause mortality and a 31% increased risk of cardiovascular deaths (both p < .05). Further analysis showed a J‐shaped association between KDI and mortality, with the risk increasing dramatically when KDI exceeded 0.27. CONCLUSION: Elevated KDI levels were significantly associated with increased mortality from all causes and CVD among individuals with hypertension. We recommend routine testing of eGFR and uACR in hypertensive patients, and using KDI as a tool to identify individuals who are most likely to benefit from preventive therapies.