African Americans are affected disproportionately by heart disease and chronic kidney disease, which is a risk factor for heart failure. Researchers in this study looked at incidence of heart failure and measures of kidney function in 1,124 African Americans and 1,676 whites over a mean 5.7 years to determine whether the association between markers of kidney function and risk of heart failure is also disproportionately present in African Americans. The analysis revealed that African Americans with the worst kidney function using cystatin C concentration or eGFR as a measure were at three times the risk of heart failure compared with those with the best kidney function, whereas the risk in whites for the worst kidney function was more modest and did not reach the level of statistical significance. At intermediate levels of kidney dysfunction, the risk that was stronger for African Americans than for whites was observable only for cystatin C concentration.
The results suggest that a modest increase in cystatin C concentration is strongly associated with increased risk of heart failure among African Americans. With increasing attention focused on heart failure prevention and the early identification of modifiable risk factors, markers such as cystatin C concentration that signify the risk associated with kidney disease in its early stages may be particularly useful. Future studies should try to elucidate the mechanisms that underlie these differences. Understanding the association between markers of kidney function and heart failure in African Americans will help guide strategies for risk reduction and prevention.