Usefulness of serial decline of kidney function to predict mortality and cardiovascular events in patients undergoing coronary angiography

Abstract

Chronic kidney disease increases cardiovascular risk and all-cause mortality. However, data on the predictive power of dynamic changes in kidney function are sparse. The aim of this research was to assess the predictive power of serial changes in kidney function on mortality and cardiovascular risk. Estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation at baseline and at follow-up in a high-risk population of 619 consecutive patients who underwent coronary angiography. The population was stratified into 3 groups with respect to decreases in eGFR: stable kidney function (no decrease in eGFR) versus a mild decline (decrease in eGFR >0 but <4 ml/min/1.73 m(2) per year) and a rapid decline in kidney function (decrease in eGFR ≥4 ml/min/1.73 m(2) per year). Mortality and nonfatal cardiovascular events were recorded over 4 years. Baseline coronary angiography revealed significant coronary stenoses (≥50%) in 368 patients (60%). Survival and event-free survival were significantly lower in patients with rapid decreases in eGFR compared with those with mild decreases (p <0.001 and p = 0.012, respectively) and stable kidney function (p <0.001 and p = 0.004, respectively). After multivariate adjustment in Cox regression analyses, the continuous variable decline in kidney function significantly predicted death (standardized adjusted hazard ratio 1.32, 95% confidence interval 1.03 to 1.70, p = 0.032) and the incidence of the composite end point death and nonfatal vascular events (hazard ratio 1.20, 95% confidence interval 1.01 to 1.43, p = 0.038). A 5 ml/min/1.73 m(2) decrease in eGFR independently conferred a 60% increase in mortality risk (p = 0.032). In conclusion, a rapid decline in kidney function is a powerful and independent new risk marker for death and vascular events.